Connective Tissue
Connective Tissue Under the Microscope (Development and Structure) Official Links Instagram Youtube Jki-discord Notes & Illustrations Quizzes Summary & Transcript 📢 Currently, there is no PDF for this video.If you’re interested in having one, feel free to send an inquiry, and I may create it in the future. BUT! There’s a quiz available in the next tab. 12345678910 Connective Tissue – QUIZ Test your understanding with 10 random multiple-choice questions from the question bank. You're in the preview mode. Note: All elements work correctly on the front end. 1 / 10 Which connective tissue cell is derived from monocytes and involved in immune defense? A) Mast cells B) Fibroblasts C) Macrophages D) Plasma cells Macrophages are derived from monocytes and play a role in immune defense and phagocytosis. 2 / 10 Which component of the extracellular matrix provides tensile strength? A) Ground substance B) Elastic fibers C) Collagen fibers D) Reticular fibers Collagen fibers provide tensile strength in connective tissue. 3 / 10 What is the primary structural unit of collagen fibers? A) Tropocollagen B) Reticulin C) Elastin D) Proteoglycans Tropocollagen is the primary structural unit of collagen fibers. 4 / 10 Which type of collagen is found in the basal lamina? A) Type III collagen B) Type IV collagen C) Type II collagen D) Type I collagen Type IV collagen supports the basal lamina in epithelial tissues. 5 / 10 What distinguishes mesenchyme in histology? A) Hematopoietic tissue B) Embryonic tissue C) Vascular tissue D) Dense fibrous tissue Mesenchyme has nuclei and cell processes forming a syncytium in embryonic tissue. 6 / 10 What is the primary function of type V collagen fibers? A) Resists pressure B) Supports lymph nodes C) Provide tensile strength D) Connects basal lamina Type V collagen provides tensile strength and is found alongside type I collagen. 7 / 10 What is the role of Matrix Metalloproteinase in connective tissue? A) Synthesizes collagen B) Produces elastin C) Degrades ECM proteins D) Lubricates tissues Matrix Metalloproteinase degrades extracellular matrix proteins for remodeling. 8 / 10 Which connective tissue type provides structural support in tendons? A) Reticular CT B) Dense regular CT C) Dense irregular CT D) Loose CT Dense regular connective tissue provides structural support in tendons due to its parallel collagen fibers. 9 / 10 What is the origin of connective tissue? A) Mesenchyme B) Ectoderm C) Epidermis D) Endoderm Connective tissue originates from the mesoderm through mesenchyme. 10 / 10 Which cells in connective tissue are involved in wound healing? A) Adipocytes B) Myofibroblasts C) Macrophages D) Mast cells Myofibroblasts are specialized fibroblasts involved in wound healing. Your score is The average score is 0% Description This video is about the Connective Tissue 🔹 Development of Connective Tissue (Mesenchyme) Embryonic Development: Zygote → Blastula → Gastrula Germ Layers: Ectoderm → Skin and Nervous System Endoderm → GI Tract, Glands, Respiratory Tract Mesoderm → Connective Tissue (CT), Bones, Cartilage, Hematopoietic Cells Mesenchyme is an embryonic tissue, found near the neural tube during development. 🔹 Classification of Connective Tissue Common Origin: Mesenchyme Connective Tissue Proper: Loose CT, Dense CT CT with Special Properties: Adipose Tissue, Hematopoietic Cells, Elastin, Mucous Tissue Supportive CT: Cartilage, Bone 🔹 Composition of Connective Tissue Located under the basement membrane Consists of: Cells (Fibroblasts, Reticulocytes, Myofibroblasts) Extracellular Matrix: Fibers: Collagen, Elastin, Reticular Ground Substance: Glycosaminoglycans, Proteoglycans, Multi-Adhesive Glycoproteins Extracellular Fluid 🔹 Dense Connective Tissue Regular Dense CT: Found in tendons, collagen fibers aligned. Irregular Dense CT: Found in deep dermis, collagen fibers arranged randomly. 🔹 Collagen Fiber Types Type 1: Resistant to tension. Type 2: Resistant to pressure. Type 3: Maintenance in organs. Type 4: Supports basal lamina. Type 5: Resistant to tension (works with Type 1). Type 7: Connects basal lamina with reticular lamina. Type 9 & 10: Found in cartilage and bone. 🔹 Types of Connective Tissue Fibers Elastic Fibers: Oxytalan (Strong fibrillin fibers) Elaunin Fibers (Elastin + Fibrillin) Proper Elastic Fibers (Elastin + Fibrillin) Reticular Fibers: Consist of Type 3 Collagen. Produced by Reticulocytes. Histology: Found in lymph nodes. 🔹 Ground Substance Located between cells and fibers. Acts as a lubricant and barrier against invaders. Contains Glycosaminoglycans, Proteoglycans, Multi-adhesive Glycoproteins. 🔹 Histology of Connective Tissue Cells Macrophage: From bone marrow, bean-shaped nucleus. Mast Cell: Large, contains granules with histamine and heparin. Plasma Cell: Derived from B-Lymphocytes, “cartwheel” nucleus. White Adipocyte: Energy storage, nucleus at the periphery. Brown Adipocyte: Found in newborns, rich in mitochondria. 🔹 Challenge at the End of the Video! Transcript Introduction0:00hello and welcome to another video in0:02this video I’m gonna cover the basics of0:04connected tissue in terms of histology0:06so as you probably know we have four0:08main types of tissue in the body we have0:11epithelial tissue we have nervous tissue0:13we have muscle tissue and connective0:15tissue so in this video I’m going to0:17mainly focus on the connective tissue0:19all right so the first thing we start0:21with is the development of connective0:23tissue CT stand for connective tissue0:25what I’m gonna mention the mesenchyme0:27and I’m also going to talk about the0:29classification of connective tissue and0:31then I’m going to talk about the0:32extracellular matrix which include the0:35fibroblast types of dense connective0:36tissue reticular tissue and ground0:39substance and I’m also going to talk0:40about the cells in connective tissue0:42which include the macrophage must cell0:45plasma cell and the two different types0:48of adipocyte we have or a so let’s startDevelopment of Connective Tissue0:51with the development of connective0:52tissue so it all starts when sperm0:55fertilizes an egg and becomes what is0:57called a zygote and then the zygote is1:00going to divide a lot and become a ball1:02of cells called a blastula and then the1:05blaster is going to keep dividing and1:07become what is called a gastrula and1:10already here you can see that the cells1:12are starting to differentiate you can1:14see that you can have an outer layer in1:16blue and inner layer in orange and then1:19a middle layer in green all right so the1:22outer layer in blue right here we call1:24this one the ectoderm1:25and the ectoderm is eventually going to1:28form things like the skin and nervous1:30system alright and the inner layer in1:33orange we call
What Is Epithelial Tissue?
What Is Epithelial Tissue? Official Links Instagram Youtube Jki-discord Notes & Illustrations Quizzes Summary & Transcript 📢 Currently, there is no PDF for this video.If you’re interested in having one, feel free to send an inquiry, and I may create it in the future. BUT! There’s a quiz available in the next tab. 12345678910 Epithelial Tissue – QUIZ Test your understanding with 10 random multiple-choice questions from the question bank. You're in the preview mode. Note: All elements work correctly on the front end. 1 / 10 Which structure anchors epithelial cells to one another? A) Tight junctions B) Gap junctions C) Desmosomes D) Hemidesmosomes Desmosomes anchor epithelial cells together to provide structural integrity. 2 / 10 What is the primary function of simple cuboidal epithelium? A) Filtration B) Secretion and absorption C) Diffusion D) Protection Simple cuboidal epithelium functions in secretion and absorption, often in glands and renal tubules. 3 / 10 Where is transitional epithelium most commonly found? A) Lungs B) Skin C) Stomach D) Urinary bladder Transitional epithelium is found in the urinary system, including the bladder and ureters. 4 / 10 Which epithelium specializes in sensory perception? A) Transitional epithelium B) Simple squamous C) Neuroepithelium D) Stratified squamous Neuroepithelium is specialized for sensory perception, found in taste buds and olfactory epithelium. 5 / 10 Which epithelium forms the outermost layer of the skin? A) Stratified squamous keratinized B) Simple squamous C) Simple cuboidal D) Transitional epithelium Stratified squamous keratinized epithelium forms the outermost layer of the skin. 6 / 10 What type of epithelial tissue is found in alveoli? A) Stratified squamous B) Transitional epithelium C) Simple squamous D) Simple cuboidal Simple squamous epithelium facilitates gas exchange in the alveoli. 7 / 10 What is the role of basal lamina in epithelial tissue? A) Produces mucus B) Facilitates blood flow C) Forms cell junctions D) Provides structural support Basal lamina provides structural support and acts as a filter for molecules. 8 / 10 What is the primary location of simple squamous epithelium in the kidney? A) Loop of Henle B) Bowman's capsule C) Collecting duct D) Proximal tubule Simple squamous epithelium lines the Bowman’s capsule in the kidney. 9 / 10 Which epithelial cell type has a brush border of microvilli? A) Transitional epithelium B) Stratified squamous C) Simple cuboidal D) Simple columnar Simple columnar epithelium with microvilli forms the brush border, aiding absorption in intestines. 10 / 10 Which type of epithelium is specialized for rapid diffusion and filtration? A) Simple squamous epithelium B) Transitional epithelium C) Simple columnar D) Stratified squamous Simple squamous epithelium is specialized for diffusion and filtration. Your score is The average score is 0% Description This video covers the topic “What Is Epithelial Tissue?” 🔹 Introduction to Epithelial Tissue The body consists of four main tissue types: epithelial, nervous, muscle, and connective. Epithelial tissue is divided into: Covering epithelium: Lines surfaces. Glandular epithelium: Secretes substances. 🔹 Development & Structure Forms early from a zygote, developing through stages like the blastula and gastrula before differentiating into specialized tissues. Key surfaces: Apical: Free surface. Lateral: Contains cell junctions. Basal: Attached to the basement membrane. 🔹 Cell Junctions & Basement Membrane Tight junctions: Prevent leakage. Gap junctions: Allow communication & ion transport. Adherens & desmosomes: Provide structural support. Basement membrane: Anchors epithelium & aids nutrient diffusion. 🔹 Classification of Epithelial Tissue Layers: Simple (one layer) vs. Stratified (multiple layers). Cell shapes: Squamous (flat), Cuboidal (cube-like), Columnar (tall). 🔹 Types of Epithelium & Locations Simple Squamous: Found in alveoli, aids gas exchange. Simple Cuboidal: Kidney tubules & glands, functions in secretion & absorption. Simple Columnar: Intestinal lining, specialized for absorption (often with microvilli). Stratified Squamous: Found in skin & mouth; can be keratinized (dry) or non-keratinized (moist). Transitional Epithelium: Adaptable, found in the urinary bladder, allowing stretching. Glandular Epithelium: Includes: Endocrine glands: Hormone secretion. Exocrine glands: Secretion to surfaces. 🔹 Neuroepithelium Specialized epithelial cells involved in sensory functions, linked to the nervous system. 🔹 Histological Perspectives Epithelial tissue is best understood through microscopic slides, helping in the identification of different types. Transcript Introduction 0:00 hello and welcome to another video in this video I want to talk about the epithelial tissue so as you probably 0:05 know the body consists of four type of tissues we have epithelial tissue nervous and muscle and connective tissue 0:11 and each of these tissue types have under group so in this video we’re going to cover the epithelial tissue look at 0:18 their under group and how they are divided into the body and we’re also gonna see the development of epithelial 0:24 tissue and at the end of this video I’m gonna put some random at the feel of the tissue so you can try to pause the video 0:30 and try to guess which cell types you’re looking at so talking about epithelial tissue you’re gonna find two main types 0:36 we have the covering epithelia and we have glandular epithelium and then I’m gonna talk a lot about glandular fever 0:42 as most of the times when we look at epithelial tissue you can think of covering epithelia but I’m gonna mention 0:49 the most important structures you’ll find the glandular epithelium pourtant to know so covering epithelia is called 0:57 covering because this covers the structures you have in the body you know the skin cells gonna composed of the 1:02 epithelial tissue you have the outside surfaces of organs gonna be epithelial 1:09 tissue and also going to line the internal surfaces of organs so as an example of that if you look at this 1:14 intestines right here you can see that you can see if a fatty tissue covering the external surfaces of the the 1:23 intestines but it’s also going to line the internal surfaces of it you can have different types of epithelial tissue 1:29 covering and lining but they’re all gonna be a Patil tissue now when you talk about glandular epithelium you can 1:36 you
What is HISTOLOGY?
What is HISTOLOGY? A quick TOUR Official Links Instagram Youtube Jki-discord Notes & Illustrations Quizzes Summary & Transcript 📢 Currently, there is no PDF for this video.If you’re interested in having one, feel free to send an inquiry, and I may create it in the future. BUT! There’s a quiz available in the next tab. 12345678910 What is HISTOLOGY? – QUIZ Test your understanding with 10 random multiple-choice questions from the question bank. You're in the preview mode. Note: All elements work correctly on the front end. 1 / 10 Who first used the term “cell” in the context of biology? A) Rudolf Virchow B) Robert Hooke C) Louis Pasteur D) Antonie van Leeuwenhoek Robert Hooke coined the term “cell” when observing cork tissue under a microscope. 2 / 10 What is the main component of the microtome used in histology? A) Objective lens B) Stage C) Condenser lens D) Blade A microtome is used to cut tissue into ultra-thin sections. 3 / 10 What substance is commonly used for fixation in histology? A) Xylene B) Ethanol C) Paraffin D) Formalin Formalin is commonly used for fixation. 4 / 10 What type of fixation is most commonly used for preserving tissue samples? A) Ethanol B) Formalin C) Paraffin D) Xylene Formalin fixation is widely used for preserving tissue samples. 5 / 10 Which cellular component is specifically highlighted by eosin staining? A) Golgi apparatus B) Cytoplasm C) Ribosomes D) Nucleus Eosin stains the cytoplasm and extracellular matrix pink. 6 / 10 Which microscope provides the highest magnification and resolution? A) Phase-contrast microscope B) Scanning electron microscope C) Transmission electron microscope D) Brightfield microscope A transmission electron microscope provides the highest magnification and resolution. 7 / 10 What is the primary difference between prokaryotic and eukaryotic cells? A) Prokaryotes have organelles B) Both lack nuclei C) Eukaryotes have nuclei D) Both have nuclei Eukaryotic cells have a nucleus, while prokaryotic cells do not. 8 / 10 Which microscope is best for observing intracellular organelles at a high resolution? A) Transmission electron microscope B) Fluorescence microscope C) Phase-contrast microscope D) Light microscope Transmission electron microscopes are ideal for observing intracellular organelles at high resolution. 9 / 10 Which type of microscopy is suitable for observing live cells in real time? A) Brightfield microscopy B) Electron microscopy C) Fluorescence microscopy D) Phase-contrast microscopy Phase-contrast microscopy is ideal for observing live cells without staining. 10 / 10 What is the primary purpose of histological staining? A) Dehydrate tissues B) Enhance visualization C) Embed tissues D) Fix tissues Staining enhances the visualization of cellular and tissue structures. Your score is The average score is 0% Description This video is about histology, its history, and how histological slides are prepared. In this video, I cover: Short history of histology: First light microscope and early discoveries. Basic cell properties: Differences between prokaryotic and eukaryotic cells. Microscopy techniques: Light Microscope: Brightfield Phase-Contrast Darkfield Fluorescence Microscope Transmission Electron Microscope (TEM) Scanning Electron Microscope (SEM) Histological slide preparation and staining: Biopsy Fixation Dehydration Paraffin Infiltration Staining (Hematoxylin & Eosin – H&E) Quick look into how to differentiate cells under a microscope (Muscle Tissue). Enjoy! Transcript Introduction0:00hello welcome to a video in this video0:01I’m going to talk about the basics of0:03cell biology where I’m going to talk0:04about the properties of the you credit0:06cell I’m also going to talk about the0:07differences between the eukaryotic cell0:09and appropriate Excel and I also got0:12attacked by the basics of histology0:13where I’m gonna take it through the0:15journey of how tissue in the human body0:17ends up looking like this so over many0:20years we have been looking at cells0:22through simple light microscopes just0:25like the one you see right here so if weHistory of Histology0:28take a quick look into the history of0:30histology there has been a lot of people0:31that have contributed to the development0:33of microscope but it’s all we really0:36started with Robert Hooke and Marshall0:38OMA Pinckney who in year 1700 were the0:42first people who used the term cell they0:45use this simple light microscope you see0:48right here and how do they work well0:51they used candle just like this one this0:54is they used this as a source of light0:56because they didn’t have any electricity0:57at that time and they use this glass1:00bulb filled with water to focus the1:03light into a specimen something they1:05wanted to observe and then that light1:07would then reflect it into this1:09microscope where they had different1:12lenses to magnify this image and with1:16those lenses they could actually see the1:19the cells of the specimen they’re1:22looking at so here’s what they looked at1:24this is a bark tissue from a tree called1:26cork oak so this is a plant you Kratt1:29Excel and each black spot we’re gonna1:32present one eukaryotic cell so in theDifferent Cellular Characteristics1:35astrology in order to understand the1:37differences between tissues in order to1:39understand the differences between1:40nervous and muscle tissues for example1:42you need to understand the different1:44cellular characteristics so I’m not1:46gonna go too much in details under this1:48because that’s gonna be for other videos1:49but mainly the first thing you want to1:52look at when you look at tissues like1:53that is what cells are you looking at1:55what are their functions here I’ve used1:58three muscle tissues as an example here2:01you see the skeletal muscles and the2:03cardiac muscles and small muscles so2:06what cells are looking at what are their2:08functions will they know that muscle2:09tissues I need to apply force so they’re2:12movable2:13so how do you differentiate between them2:14even though they have the same function2:16well you know that skeletal muscles are2:18going to be long cylindrical just like2:19you see here2:20cardiac muscles are going to be short2:22and branched some of these muscles for2:25examples for me like that2:26well this muscle is cells from a dead2:30while swarm us also I’m going to be very2:33narrow and elongated so that we’re gonna2:38be very close to each other so you need2:41to look at the shape of the cells but2:44you also need to look at the cell2:45nucleus so you know that the skeletal2:47muscles are gonna be multi nuclide and2:49they’re gonna have many nuclei it’s like2:51you see here while cardiac muscles are2:54gonna have one nucleus not be the same2:56goes
Hypersensitivity Reactions
Hypersensitivity Reactions (Type 1-4) Official Links Instagram Youtube Jki-discord Notes & Illustrations Quizzes Summary & Transcript 📢 Currently, there is no PDF for this video.If you’re interested in having one, feel free to send an inquiry, and I may create it in the future. BUT! There’s a quiz available in the next tab. 12345678910 Hypersensitivity – QUIZ Test your understanding with 10 random multiple-choice questions from the question bank. You're in the preview mode. Note: All elements work correctly on the front end. 1 / 10 What is the mechanism of action of granulysin in Type 4 hypersensitivity? A) Neutralizes cytokines B) Enhances inflammation C) Activates complement D) Induces apoptosis Granulysin induces apoptosis of target cells during Type 4 hypersensitivity. 2 / 10 Which hypersensitivity type involves immune responses against viral budding antigens? A) Type 4 B) Type 3 C) Type 1 D) Type 2 Type 2 hypersensitivity occurs when antibodies target antigens during viral budding. 3 / 10 Which hypersensitivity reaction is most commonly associated with poison ivy exposure? A) Type 2 B) Type 4 C) Type 3 D) Type 1 Poison ivy causes a Type 4 hypersensitivity reaction. 4 / 10 Which cells are directly affected in Type 2 hypersensitivity? A) Epithelial cells B) Target cells C) Neutrophils D) T-cells Target cells, such as red blood cells, are destroyed by antibodies and complement in Type 2 hypersensitivity. 5 / 10 What is the function of histamine in Type 1 hypersensitivity? A) Increases vascular permeability B) Neutralizes cytokines C) Activates T-cells D) Opsonizes antigens Histamine causes vasodilation, increased vascular permeability, and bronchoconstriction. 6 / 10 What is the clinical hallmark of Type 3 hypersensitivity? A) Histamine release B) Mast cell activation C) Immune complex deposition D) Cytokine storm Immune complex deposition in tissues is the hallmark of Type 3 hypersensitivity. 7 / 10 What is the primary cell type involved in Type 1 hypersensitivity? A) T-lymphocytes B) Neutrophils C) Macrophages D) Mast cells Mast cells are key players in Type 1 hypersensitivity as they release histamine upon activation. 8 / 10 What is a key feature of Type 4 hypersensitivity? A) Delayed response B) Immediate response C) Antibody involvement D) Complement activation It is delayed, as T-cell responses take 24-72 hours to cause inflammation. 9 / 10 Which type of hypersensitivity involves antibody-dependent cell-mediated cytotoxicity? A) Type 4 B) Type 2 C) Type 3 D) Type 1 Type 2 hypersensitivity involves antibody-dependent cytotoxicity via natural killer cells. 10 / 10 What are the key effector cells in Type 3 hypersensitivity? A) Basophils B) Mast cells C) Neutrophils D) T-lymphocytes Neutrophils are key effector cells that cause tissue damage in Type 3 hypersensitivity. Your score is The average score is 0% Description This video is about Hypersensitivity and its classification. All information in my immunology videos is sourced from: Book: Immunology, Eighth Edition by David Male, Jonathan Brostoff, David Roth, and Ivan Roitt Additional research: PubMed University lecture materials Hypersensitivity: Excessive Immune Response Hypersensitivity reactions occur when the immune system responds excessively to an antigen, leading to tissue damage. Coombs and Gell Classification of Hypersensitivity: Type 1: Immediate Hypersensitivity (IgE-mediated) Type 2: Antibody-Mediated Hypersensitivity Type 3: Immune Complex Disease Type 4: Cell-Mediated Reactions Type 1 Hypersensitivity: IgE-Mediated Hypersensitivity Occurs when IgE antibodies on mast cells trigger anaphylactic shock. Factors that Induce Allergy: Pollen Inhaled particles (dust, pet dander, mold spores) Milk, fish, nuts Direct skin contact allergens Genetic predisposition plays a role in allergic hypersensitivity. Development of Type 1 Hypersensitivity: First exposure: Inhaled pollen enters the body. Phagocytosis: Langerhans cells (or other APCs) phagocytose pollen and travel to the lymph node via afferent lymphatic vessels. Sensitization Stage (in the lymph node): APCs present the antigen on MHCII to a naive T-helper cell. Three activation signals occur: TCR-MHCII, CD28-B7, and IL-4. IL-2 promotes Th0 proliferation into effector Th2 cells. B-cells that bind pollen undergo receptor-mediated endocytosis and interact with Th2, leading to IgE production. Sensitization phase duration: 6 months to 5 years. Second exposure: Pollen binds to IgE antibodies on mast cells. Mast cell degranulation: Histamine is released, leading to: Vasodilation Increased capillary permeability Bronchoconstriction Secretion of IL-5 and TNF-α Type 2 Hypersensitivity: Antibody-Mediated Immune Response Involves IgG or IgM antibodies targeting cell surface antigens. Possible Causes: Viral Budding: Some viruses place their proteins on the host cell surface, leading to antibody recognition. Blood Transfusion Reactions: Mismatched ABO blood types can trigger immune destruction of red blood cells. Drug Allergies: Some drugs can bind to cell surfaces, making them targets for antibodies. Autoimmune Reactions: T-cell tolerance failure can lead to autoimmune diseases. Mechanism: Antibodies bind to surface antigens. Activation of the Complement System: MAC formation leads to cell lysis. C3b opsonization allows phagocytes to bind via C3b receptors. Neutrophils and NK cells recognize and destroy the antibody-coated cells. Type 3 Hypersensitivity: Immune Complex Disease Immune complexes (antigen-antibody complexes) form and deposit in tissues, causing inflammation. Pathophysiology: Normally, immune complexes are cleared by the liver and spleen. If they persist, they can become trapped in vessel walls, activating the complement system. Neutrophils, basophils, and mast cells respond, leading to inflammation (Arthus Reaction). Platelets aggregate, further worsening the reaction. Examples: Serum Sickness: If bitten by a venomous snake, injecting anti-venom (pre-formed antibodies) can cause immune complex formation. Systemic Lupus Erythematosus (SLE): Persistent immune complexes cause chronic inflammation. Type 4 Hypersensitivity: Cell-Mediated (Delayed-Type Hypersensitivity) Involves Th1 and T-cytotoxic (T-cyt) cells triggering local inflammation. Example: Tuberculin Skin Test (Mantoux Test) Injection: Tuberculin is injected into the skin. Phagocytosis: Macrophages or Langerhans cells engulf tuberculin. Antigen Presentation: APCs travel to the lymph node and present tuberculin on: MHCII to naive Th0 cells. MHCI to naive T-cytotoxic cells. Th1 Activation: Three activation signals occur. IL-2 helps differentiation into effector Th1. T-cyt Activation: IL-2 and IFN-γ promote differentiation into effector T-cytotoxic cells. Effector T-cyt expresses FasL, which binds Fas on infected cells. Releases perforins and granzymes, causing apoptosis. Second exposure: Phagocytes activate effector Th1 and T-cytotoxic cells. Th1 releases IFN-γ to activate macrophages. Macrophages release inflammatory cytokines
Cellular Immunity
Cellular Immunity (T-Cytotoxic, NK Cell, Macrophage, Immunity To Virus, Interferons) Official Links Instagram Youtube Jki-discord Notes & Illustrations Quizzes Summary & Transcript 📢 Currently, there is no PDF for this video.If you’re interested in having one, feel free to send an inquiry, and I may create it in the future. BUT! There’s a quiz available in the next tab. 12345678910 Cellular Immune Response – QUIZ Test your understanding with 10 random multiple-choice questions from the question bank. You're in the preview mode. Note: All elements work correctly on the front end. 1 / 10 What is the role of CD28 on T-cytotoxic cells? A) Activates NK cells B) Enhances cytokine release C) Suppresses inflammation D) Provides co-stimulation CD28 binds B7 on APCs to provide a co-stimulatory signal for T-cell activation. 2 / 10 What is the role of IL-12 in cellular immunity? A) Neutralizes cytokines B) Suppresses Th2 response C) Activates B cells D) Promotes Th1 differentiation IL-12 is released by macrophages to promote Th1 differentiation and NK cell activation. 3 / 10 What is the primary function of Type I interferons (IFN-alpha and IFN-beta)? A) Activate Th2 cells B) Inhibit viral replication C) Reduce inflammation D) Neutralize antibodies Type I interferons inhibit viral replication and increase MHCI expression. 4 / 10 What cytokine promotes Th1 differentiation and inhibits Th2 function? A) IL-2 B) TNF-alpha C) IL-4 D) IFN-gamma IFN-gamma promotes Th1 differentiation and reduces Th2 response. 5 / 10 Which innate immune cells release cytokines to initiate a cellular immune response? A) B-cells B) Macrophages C) NK cells D) Dendritic cells Macrophages release IL-12 and other cytokines to initiate cellular immunity. 6 / 10 What triggers natural killer cells to kill a target cell? A) Activation of Th2 cells B) Absence of MHCI C) Presence of CD4 D) High MHCI expression NK cells kill cells lacking MHCI or expressing stress signals. 7 / 10 What is the role of FasL on T-cytotoxic cells? A) Inhibits T-cell growth B) Promotes Th1 differentiation C) Binds to cytokines D) Induces apoptosis FasL binds to Fas on infected cells, inducing apoptosis. 8 / 10 Which receptor on NK cells inhibits killing when bound to MHCI? A) NKR-P1 B) Ly49 C) CD16 D) FasL Ly49 receptor binds MHCI and sends an inhibitory signal to NK cells. 9 / 10 What cytokine is involved in recruiting neutrophils during a cellular immune response? A) TNF-alpha B) IL-4 C) IL-12 D) IL-8 IL-8 recruits neutrophils during cellular immunity. 10 / 10 What is the outcome of decreased MHCI expression on virus-infected cells? A) Promotes antibody production B) Enhances inflammation C) Triggers NK cell cytotoxicity D) Activates Th2 cells Decreased MHCI triggers NK cells to kill the infected cells. Your score is The average score is 0% Description PS! At 02:00, I incorrectly wrote MHCII instead of MHCI in the list of activation signals. I apologize for the typo, viewers! This video covers the Cellular Immune Response, its effectors, and mechanisms of immunity against viruses. All information in my immunology videos is sourced from: Book: Immunology, Eighth Edition by David Male, Jonathan Brostoff, David Roth, and Ivan Roitt Additional research: PubMed University lecture materials Types of Immune Responses: Humoral Immune Response Cellular Immune Response Immunological Memory/T-cell Tolerance Hypersensitivity Cellular Immune Response Targets: Virus-infected cells Oncogenic cells (Cancer cells) Transplanted cells These are controlled through MHCI on their surface. Effector Cells in Cellular Immunity: T-Cytotoxic Cells Natural Killer (NK) Cells Macrophages T-Cytotoxic Lymphocyte Activation: Requires three activation signals: T-cell receptor (TCR) with CD8 and CD3 binds to MHCI. CD28 – B7 interaction. Cytokines (IFN-γ and IL-2) from Th1. Once activated, T-cytotoxic cells express Fas Ligand (FasL), which binds to Fas on infected cells. They then release perforins and granzymes to induce apoptosis. Natural Killer (NK) Cells: Differentiate between healthy and infected cells based on surface receptors: NK Cell Surface Receptors: Ly49: Binds to MHCI and sends a negative signal to prevent NK activation. NKR-P1: Recognizes proteins on infected cells and activates NK cells. Fas-L: Recognizes Fas-expressing sick cells. CD16: Binds to the Fc portion of antibodies, triggering antibody-dependent cytotoxicity. IL-2 receptor: Binds to IL-2 and activates NK cells. Surface markers: CD56+, CD16+, and CD2 (adhesion molecule). Activated NK Cells Release: TNF-α: Activates endothelium and induces fever. IFN-γ: Enhances cytotoxicity, activates macrophages, and further stimulates NK cells. Scenario of Cytotoxic Immune Response: A virus infects a normal cell, making it a non-professional APC (does not express B7). If a professional APC phagocytoses the infected cell, it presents viral fragments on MHC I and MHC II. T-cytotoxic cell binds to MHC I via TCR-MHCI and CD28-B7. Naïve Th0 binds to MHC II via TCR-MHCII, B7-CD28, and receives IL-12 → releases IL-2 (autocrine) → differentiates into Th1. Effector Th1 releases IFN-γ and IL-2 to fully activate T-cytotoxic cells. Effector T-cytotoxic cells express FasL, bind to Fas on infected cells, and release Granzyme B and Perforins to induce apoptosis. Th1 activates macrophages via CD40L-CD40 and IFN-γ to eliminate remaining viral particles. Immunity to Viruses: Adaptive Immune Response: Involves T-cells, resulting in immunological memory and antibody production. Innate Immune Factors: General Factors: Viruses have specific cell receptors (tropism). Macrophages release inflammatory cytokines, inducing fever. Secretory factors: Feces, saliva, gastric juice. Humoral Factors: Complement System (opsonization). Acute-phase proteins (Mannose Binding Lectin and C-Reactive Protein). Cellular Factors: Phagocytosis Interferons Interferon System: Interferons (IFNs) are cytokines released in response to viral infection. Types of Interferons: IFN-α: Released by leukocytes. IFN-β: Released by fibroblasts. IFN-γ: Released by immune cells. Classification: Type 1 IFN (IFN-α, IFN-β): Inhibits protein synthesis and DNA replication in virus-infected cells. Increases MHCI expression on all cells. Activates NK cells. Stimulates T-helper and B-lymphocytes. Type 2 IFN (IFN-γ): Reduces Th2 response. Enhances Th1 response. Activates NK cells and macrophages. Differentiates B-cells into IgG-secreting plasma cells. Antibodies Against Viruses: 1st week: IgM (Neutralizes circulating viruses). 2nd week: IgG (Targets circulating and extravascular viruses). IgA: Protects mucosal surfaces and prevents reinfection. Summary: When a cell is infected by a virus: It expresses Fas, which binds to
Humoral Immunity
Humoral Immunity (ALL Steps) Official Links Instagram Youtube Jki-discord Notes & Illustrations Quizzes Summary & Transcript 📢 Currently, there is no PDF for this video.If you’re interested in having one, feel free to send an inquiry, and I may create it in the future. BUT! There’s a quiz available in the next tab. 12345678910 Humoral Immunity – QUIZ Test your understanding with 10 random multiple-choice questions from the question bank. You're in the preview mode. Note: All elements work correctly on the front end. 1 / 10 What is the role of CRP (C-reactive protein) during inflammation? A) Acts as an opsonin B) Enhances cytokine release C) Inhibits T-cell function D) Stimulates IgE CRP acts as an opsonin and activates the classical complement pathway. 2 / 10 What is the primary purpose of the humoral immune response? A) Direct phagocytosis B) Promote cell apoptosis C) Antibody production D) Inhibit T-cell activation To target extracellular pathogens through antibody production. 3 / 10 What cytokine activates B-cells during T-cell-dependent B-cell differentiation? A) IL-6 B) IL-4 C) TNF-alpha D) IL-12 IL-4 is essential for activating B-cells during T-cell-dependent B-cell differentiation. 4 / 10 What is the primary role of the humoral immune response? A) Phagocytose pathogens B) Kill infected cells C) Produce antibodies D) Release cytokines The humoral immune response involves producing antibodies to target extracellular pathogens. 5 / 10 What is the primary role of IL-6 during the humoral immune response? A) Induces apoptosis B) Suppresses Th1 response C) Activates B- and T-cells D) Inhibits inflammation IL-6 promotes the activation of B- and T-lymphocytes. 6 / 10 What triggers T-independent B-cell activation? A) CD40-CD40L B) IL-4 C) Direct carbohydrate binding D) IL-12 T-independent activation occurs when carbohydrates bind directly to the B-cell receptor. 7 / 10 What happens to the level of IgM during the secondary immune response? A) Decreases significantly B) Remains constant C) Increases drastically D) Stops production The level of IgM remains the same during the secondary immune response. 8 / 10 Which receptor on phagocytes binds to the Fc region of antibodies for direct opsonization? A) TLR B) CD14 C) C3b receptor D) Fc receptor The Fc receptor binds to the Fc region of antibodies to promote direct opsonization. 9 / 10 What happens to the level of IgG during a secondary humoral immune response? A) Becomes undetectable B) Remains constant C) Decreases D) Increases IgG levels increase rapidly and are higher than in the primary response. 10 / 10 How do acute-phase proteins like CRP and MBL function in humoral immunity? A) Promote phagocytosis B) Activate NK cells C) Neutralize toxins D) Opsonize and activate They act as opsonins and activate the complement system. Your score is The average score is 0% Description This video covers the humoral immune system and its role in immune responses. All information in my immunology videos is sourced from: Book: Immunology, Eighth Edition by David Male, Jonathan Brostoff, David Roth, and Ivan Roitt Additional research: PubMed University lecture materials Types of Immune Responses: Humoral Immune Response Cellular Immune Response Immunological Memory/T-cell Tolerance Hypersensitivity Steps in Humoral Immunity: Antigen Entry: Extracellular antigens enter the body. Phagocytosis and Inflammation: Professional phagocytes attack the antigen. Antigen Presentation: Peptides presented on MHC II to Th0 cells. B-cell Differentiation: Specific antibodies are produced. Phagocytosis and Inflammation: Professional Phagocytes: Neutrophils Macrophages/Monocytes Mast Cells Dendritic Cells Steps in Phagocytosis: Binding: Mannose Receptor: Binds mannose on microbial surfaces. Toll-Like Receptor (TLR): Recognizes microbial patterns. CD14: Binds lipopolysaccharide (LPS) of Gram-negative bacteria. C3b – C3b Receptor: Indirect opsonization (enhances binding). Fc-Receptor: Binds to the Fc portion of antibodies (direct opsonization). Engulfment: Formation of pseudopods to enclose the antigen. Phagosome Formation: Oxygen-dependent digestion via Reactive Oxygen Species (ROS). Lysosome Fusion: Breakdown of microbes via: Enzymes (Proteolytic, Hydrolytic) Antimicrobial Peptides (Defensins) Acidic Reactions (Low pH) Lactoferrin (Neutrophils) Antigen Presentation: Fragments of the microbe are displayed on MHC II. Pro-Inflammatory Cytokine Release: IL-8: Chemotaxis for leukocytes. IL-1: Activates T-lymphocytes and macrophages. IL-6: Activates T- and B-lymphocytes. TNF-α: Activates endothelium, promoting neutrophil extravasation. IL-12: Activates natural killer (NK) cells. Systemic Response of IL-1, IL-6, and TNF-α: They act as endogenous pyrogens (cause fever). Travel to the hypothalamus → Release Prostaglandin E2 (PGE2) → Increases body temperature. IL-6 travels to the liver → Stimulates release of acute-phase proteins (CRP and MBL). Incomplete Phagocytosis: Some microbes evade destruction inside the phagocyte: Listeria: Releases Listeriolysin. Mycobacterium: Releases Catalase. Activation of Naïve T Helper Cells: Three activation signals are needed: 1st Signal: TCR (with CD4/CD3) binds to MHC II. 2nd Signal: B7 binds to CD28. 3rd Signal: IL-4 (from mast cells/Th1). Naïve Th0 releases IL-2 (autocrine) to promote its growth. Th0 undergoes clonal expansion and differentiates into effector Th2 cells. Effector Th2 Functions: Expresses CD40L to assist B-cell activation. Releases cytokines: IL-10: Suppresses Th1 function. IL-4, IL-5, IL-6: Stimulate B-cell differentiation. B-Cell Activation in Secondary Lymphoid Organs: B-cells have B-cell Receptors (BCR): IgD/IgM with Iga and Igb signaling components. B-cells migrate to the secondary follicle to interact with T-cells. Three Activation Signals for Naïve B-Cell Differentiation (T-cell Dependent): 1st Signal: BCR binds to antigen. 2nd Signal: B-cell binds to active Th2 via: MHC II – TCR CD40 – CD40L 3rd Signal: IL-4, IL-5, IL-6, IL-10, IL-2, IFN-γ (determines antibody class). B-cells then differentiate into: Memory B-cells (long-term immunity). Plasma Cells (produce antibodies). T-Independent B-Cell Differentiation: Occurs when BCR binds to polysaccharides or carbohydrate antigens. Strong activation signal → Differentiation into IgM-secreting Plasma Cells. Does not produce memory B-cells. Primary vs. Secondary Humoral Immune Response: Primary Response: First exposure: IgM is produced first, followed by IgG. IgG levels are higher than IgM. Secondary Response: Second exposure: IgM response is the same. IgG response is stronger and faster due to memory B-cells. Transcript No transcript available for this video. Notes & Illustrations Quizzes Summary & Transcript 📢 Currently, there is no PDF for this video.If you’re interested in having one, feel free to send an inquiry, and I may create it in the future. BUT! There’s a quiz available
T-Cells
T- Cells (Development, Helper CD4+, Cytotoxic CD8+, Th17, Tolerance) Official Links Instagram Youtube Jki-discord Notes & Illustrations Quizzes Summary & Transcript 📢 Currently, there is no PDF for this video.If you’re interested in having one, feel free to send an inquiry, and I may create it in the future. BUT! There’s a quiz available in the next tab. 12345678910 T-Cells – QUIZ Test your understanding with 10 random multiple-choice questions from the question bank. You're in the preview mode. Note: All elements work correctly on the front end. 1 / 10 What organ is responsible for T-cell maturation? A) Lymph nodes B) Bone marrow C) Thymus D) Spleen The thymus is the primary site for T-cell maturation. 2 / 10 What surface molecule mediates macrophage activation by Th1 cells? A) FasL B) MHC I C) CD40L D) IL-2 CD40L on Th1 cells interacts with CD40 on macrophages to activate them. 3 / 10 What is the primary function of T-regulatory cells? A) Activate macrophages B) Promote Th1 function C) Suppress immune response D) Stimulate antibody production T-regulatory cells suppress the immune response and prevent autoimmunity. 4 / 10 What is the purpose of positive selection in T-cell development? A) Prevent apoptosis B) Recognize self MHC C) Induce clonal expansion D) Check for antigen recognition Positive selection ensures that T-cells can recognize self MHC molecules. 5 / 10 Which molecule is involved in the first activation signal for naive T-cells? A) MHC-TCR B) CD40-CD40L C) FasL-Fas D) B7-CD28 The interaction between MHC and TCR (with CD4 or CD8) constitutes the first activation signal. 6 / 10 What is the role of IL-10 released by T-regulatory cells? A) Recruit neutrophils B) Suppress Th1 response C) Stimulate Th2 cells D) Activate dendritic cells IL-10 suppresses Th1 responses and promotes immune tolerance. 7 / 10 What role does IL-2 play in T-cell activation? A) Activates dendritic cells B) Enhances T-cell growth C) Promotes inflammation D) Suppresses Th1 cells IL-2 promotes the clonal expansion of activated T-cells. 8 / 10 Which T-cell subset is most effective against viral infections? A) Cytotoxic T-cells B) T-regulatory cells C) Th1 cells D) Th17 cells CD8+ T-cells (cytotoxic T-cells) are highly effective against viral infections. 9 / 10 What happens during clonal expansion of T-cells? A) Present antigens B) Proliferate C) Suppress inflammation D) Undergo apoptosis Activated T-cells proliferate and differentiate during clonal expansion. 10 / 10 How do T-cells recognize antigens? A) CD40-CD40L B) TCR on MHC C) TGF-beta D) BCR on MHC T-cells recognize antigens via the T-cell receptor (TCR) presented on MHC molecules. Your score is The average score is 0% Description This video is about T-Lymphocyte Development and Function. All information in my immunology videos is sourced from: Book: Immunology, Eighth Edition by David Male, Jonathan Brostoff, David Roth, and Ivan Roitt Additional research: PubMed University lecture materials Development of T-Lymphocytes: Origin: In red bone marrow as Multipotent Lymphoid Stem Cells. Migration: Travel to the Thymus for further development. Thymus: Grows to its maximum size around puberty, then gradually replaced by fat tissue. Stages of T-cell Development in the Thymus: Double Negative Stage: Ensure the cell lacks CD4/CD8. Double Positive Stage: Ensure the cell expresses CD4/CD8. Positive Selection: Ensure recognition of self MHC. Negative Selection: Ensure no recognition of self-antigens. Single Positive Selection: Cells become either: CD4+ T-Helper Cells CD8+ Cytotoxic T-Cells Survivors travel to secondary lymphoid organs. If a cell fails any stage, it undergoes apoptosis. CD4+ Activation – T Helper Cells: Requires 3 activation signals to activate naïve T-cells: 1st Activation Signal: MHC – TCR (Receptor + CD4 + CD3). 2nd Activation Signal: B7 – CD28. 3rd Activation Signal: Cytokines: IL-4: Induces differentiation into Th2. IL-12: Induces differentiation into Th1. Activated T-helper cells secrete IL-2 (autocrine) for self-proliferation. Functions of Activated T-Helper Cells: Th2 Cells: IL-10: Suppresses Th1 response. IL-4, IL-5, IL-6: Stimulate B-cells for IgG, IgE, and IgA synthesis. Th1 Cells (Inflammatory T-Helper Cells): IFN-γ (Interferon Gamma): Activates macrophages, promotes IgG synthesis, and inhibits Th2 response. IL-2: Helps the growth of B-cells and T-cells. CD8+ Activation – Cytotoxic T-Cells: Virus-infected cells present antigen on: MHC I: Non-professional APCs. MHC II and MHC I: Professional APCs. Activation: T-Cytotoxic Cell binds to MHC I through TCR (3 activation signals required). Th0 binds to MHC II and differentiates into Th1, releasing: IFN-γ and IL-2 to enhance cytotoxic T-cell activity. Mechanism of Killing: T-cytotoxic cells undergo clonal expansion and express Fas-L to target Fas-expressing infected cells. Release of: Perforin: Creates holes in the infected cell membrane. Granzyme B: Induces DNA fragmentation. Th17 Cells: Important in fighting fungal infections. Severe fungal infections occur in immunosuppressed individuals. Th17 Cell Development: Macrophages phagocytose fungi. Present three activation signals to naïve T-helper cells (Th0). Macrophages release: IL-1, IL-6, IL-23 Transforming Growth Factor Beta (TGF-β) → This differentiates Th0 into Th17. Th17 Cell Functions: IL-17: Recruits neutrophils. Neutrophils: Promote inflammation via: Granule release Lysozymes Reactive oxygen species IL-22 and IL-17: Stimulate epithelial cells to produce antimicrobial defensins. T-Cell Tolerance: Eliminates cells that react to self-antigens. Central Tolerance (In Thymus): Kills self-reactive T-cells before they mature. Peripheral Tolerance (Outside Thymus): Self-reactive T-cells that escape to secondary lymphoid organs are inhibited through: Clonal deletion (Direct inactivation). T-Regulatory Cells (T-reg). T-Regulatory Cell (T-Reg) Functions: IL-35: Suppresses immune function. IL-10: Decreases Th1 function. TGF-β: Inhibits macrophages. Regulates dendritic cells to prevent excessive immune response. Monitors IL-2 levels to regulate immune function. How Many Days Does It Take to Gain Immunological Memory? Starts as a naïve cell. Clonal expansion: ~7 days. Effector response follows. Decreases until it becomes a memory cell. Memory cells persist and slowly decline after 14 days. Transcript Introduction0:00hello and welcome to another video in0:01this video I’m going to talk about the0:03t-lymphocytes development and functions0:05so let’s start with the development someT-Cell Development0:08bones in your body has what we call0:09yellow bone marrow consisting mainly of0:11fat cells and we also have spongy bone0:15what we call red bone marrow which is0:16very very vascular lead and in the red0:19bone marrow most of our red blood cells0:21and
Antigen Presenting Cells
Antigen Presenting Cells (B-cells, Macrophage, Dendritic Cell) Official Links Instagram Youtube Jki-discord Notes & Illustrations Quizzes Summary & Transcript 📢 Currently, there is no PDF for this video.If you’re interested in having one, feel free to send an inquiry, and I may create it in the future. BUT! There’s a quiz available in the next tab. 12345678910 Antigen Presenting Cells – QUIZ Test your understanding with 10 random multiple-choice questions from the question bank. You're in the preview mode. Note: All elements work correctly on the front end. 1 / 10 What type of immunity is mediated by antigen-presenting cells? A) Adaptive immunity B) Passive immunity C) Innate immunity D) Autoimmunity Antigen-presenting cells are involved in adaptive immunity by presenting antigens to T- and B-cells. 2 / 10 What cytokines are crucial for the differentiation of Th0 cells into Th1 cells? A) IL-10 B) IL-8 C) IL-4 D) IL-12 IL-12 released by macrophages is crucial for Th0 to Th1 differentiation. 3 / 10 What surface molecule on dendritic cells enhances their ability to activate T-cells? A) CD40 B) ICAM-1 C) MHC I D) B7 The B7 molecule on dendritic cells provides co-stimulatory signals to T-cells. 4 / 10 What is the function of B7 molecules on APCs? A) Presents antigens B) Provides co-stimulation C) Causes apoptosis D) Releases cytokines B7 provides the second activation signal to T-cells via interaction with CD28. 5 / 10 Where are B cells located in the lymph nodes? A) Germinal Center B) Cortex C) Medulla D) Paracortex B cells are primarily found in the outer cortex of the lymph nodes. 6 / 10 What happens when immature dendritic cells phagocytose antigens? A) Undergo apoptosis B) Become NK cells C) Migrate to lymph nodes D) Release cytokines Immature dendritic cells migrate to lymph nodes and express co-stimulatory molecules like B7. 7 / 10 What surface receptor on macrophages binds IgG-opsonized pathogens? A) CD40 B) MHC I C) Fc receptor D) TLR2 Fc receptors on macrophages bind to the Fc region of IgG, aiding in phagocytosis. 8 / 10 Which molecule on APCs provides the co-stimulatory signal to naive T-helper cells? A) MHC I B) B7 C) CD40 D) ICAM-1 The B7 molecule on APCs interacts with CD28 on T-helper cells to provide the second activation signal. 9 / 10 Which APC is located in epithelial tissues and migrates to lymph nodes upon activation? A) Macrophages B) B-Lymphocytes C) Langerhans Cells D) NK Cells Langerhans cells, a type of dendritic cell, are found in epithelial tissues and migrate to lymph nodes. 10 / 10 What cytokine is a major chemotactic factor released by activated macrophages? A) IL-1 B) IL-6 C) IL-8 D) TNF-alpha IL-8 is a key chemotactic factor for recruiting neutrophils and leukocytes. Your score is The average score is 0% Description This video is about Antigen Presenting Cells (APCs). All information in my immunology videos is sourced from: Book: Immunology, Eighth Edition by David Male, Jonathan Brostoff, David Roth, and Ivan Roitt Additional research: PubMed University lecture materials What Are Antigen Presenting Cells (APCs)? Phagocytose microorganisms and present them on MHC I or MHC II. Express B7 (Co-stimulatory molecule for T-cell activation). Present MHC II to naïve T-Helper Cells (CD4+). Require three activation signals to activate naïve T-helper cells: 1st Activation Signal: MHCII-TCR (CD4 and CD3) 2nd Activation Signal: B7 – CD28 3rd Activation Signal: Interleukins MHC I activates T-cytotoxic cells (CD8+). Professional Antigen Presenting Cells: B-Lymphocytes Macrophages Dendritic Cells Inactive/Unprofessional Antigen Presenting Cells: Langerhans Cells B-Lymphocytes: Produce antibodies against specific antigens. During development: B-cells randomly generate surface antibodies. If B-cells do not encounter antigens within a certain timeframe, they undergo apoptosis (Anergy). B-Lymphocyte Development: Occurs in the Spongy Bone: Starts as Pluripotent Hematopoietic Stem Cell. Pro B-Cell Pre B-Cell (Heavy chain recombination for IgM: VDJ gene) Immature B-Cell (Light chain recombination: VJ gene, IgM development complete) Mature B-Cell: Expresses both IgM and IgD on the surface. Checked for self-reactivity. If non-self-reactive → Travels to secondary lymphoid organs (Lymph nodes, spleen, Peyer’s patches). B-Lymphocyte Activation: B-Cell Receptor (BCR): Consists of IgD/IgM and signaling chains (Igα and Igβ). B-Cells reside in the outer cortex of lymph nodes. Steps: BCR binds to antigen. Endocytosis of BCR-antigen complex. Antigen is presented on MHC II to Th2 or Th0. Th2 binds to the activated B-cell through: CD40L-CD40 interaction TCR-MHCII interaction Cytokines (IL-4, IL-5, IL-10, IL-6, IL-2, IFN-γ) help B-cell differentiate. B-Cell becomes a Memory B-cell or Plasma Cell. T-cell Dependent B-cell Differentiation: Produces IgA, IgE, or IgG. T-cell Independent B-cell Differentiation: Rapidly produces IgM when polysaccharides bind to BCR (No memory B-cells produced). Macrophage Development: Pluripotent Hematopoietic Stem Cell Mono Stem Cell Pro-monoblast Monoblast Pro-monocyte Monocyte in blood Monocyte differentiates into: Free Macrophage (in tissue) Fixed Macrophage Dendritic Cell Macrophage Functions: MHC I and MHC II expression. Fc receptors: Fc IgG (Direct Opsonization) Fc IgE C3b receptor: Binds complement protein C3b. CD14: Recognizes Lipopolysaccharides (LPS). B7: Co-stimulation for T-cell activation. Active Macrophage Releases: Interleukin 12 (IL-12): Differentiates Th0 into Th1 and activates Natural Killer (NK) cells. Interleukin 8 (IL-8): Chemotaxis. Interleukin 1 (IL-1), IL-6, TNF-α: Act as endogenic pyrogens (cause fever). IL-1, IL-6, TNF-α travel to the hypothalamus → Release Prostaglandin E2 (PGE2). IL-6 travels to the liver → Causes the release of acute phase proteins. Dendritic Cells: Derived from monocytes in the blood. Highly migratory. Surface Markers: MHC I and MHC II B7 Adhesion molecules: Help bind T-lymphocytes. Langerhans Cells: Also known as immature dendritic cells. After phagocytosis, they migrate to lymph nodes and begin expressing B7. Transcript Introduction0:00hello and welcome to another video in0:01this video I’m gonna talk about the0:03different antigen presenting cells we0:05have in our body basically how they0:07develop and their characteristics soFunction of Antigen-Presenting Cells (APCs)0:10what is an antigen presenting cell these0:12cells are cells that can catch0:15microorganism and basically present them0:17on either MHC 1 or MHC 2 but these guys0:21were special with these guys is that0:23they can actually Express what is called0:24b7 and b7 is a major call simulator for0:28the T cells we have
Antibodies
Antibodies (Origin, Components, Domains, IgG, IgM, IgA, IgD, IgE) + Table Official Links Instagram Youtube Jki-discord Notes & Illustrations Quizzes Summary & Transcript 📢 Currently, there is no PDF for this video.If you’re interested in having one, feel free to send an inquiry, and I may create it in the future. BUT! There’s a quiz available in the next tab. 12345678910 Antibodies – QUIZ Test your understanding with 10 random multiple-choice questions from the question bank. You're in the preview mode. Note: All elements work correctly on the front end. 1 / 10 What type of antibody diversity is determined by differences in the variable region? A) Idiotypic differences B) Conformational epitopes C) Allotypic differences D) Isotypic differences Idiotypic differences are based on variations in the variable region. 2 / 10 What determines the antigen-binding specificity of an antibody? A) Fab fragment B) Fc fragment C) Variable region D) Constant region The variable region of the light and heavy chains binds specifically to the antigen. 3 / 10 Which antibody is capable of crossing the placenta? A) IgG B) IgM C) IgE D) IgA IgG is the only antibody that can cross the placenta and provide passive immunity to the fetus. 4 / 10 Which antibody is predominantly found on the surface of immature B cells? A) IgA B) IgD C) IgG D) IgM IgD is primarily found on the surface of immature B cells. 5 / 10 What distinguishes T-cell-dependent from T-cell-independent antibody production? A) Produces diverse isotypes B) Produces IgD only C) Produces IgE only D) No memory formation T-cell-independent responses produce mainly IgM, while T-cell-dependent responses can produce all isotypes. 6 / 10 What is the primary role of IgA? A) Mucosal immunity B) Allergic response C) Complement activation D) Placental transfer IgA is primarily involved in mucosal immunity. 7 / 10 What is the structural form of IgM in the serum? A) Pentamer B) Monomer C) Dimer D) Trimer IgM exists as a pentamer in the serum, connected by a J-chain. 8 / 10 Which immunoglobulin is most effective in neutralizing toxins? A) IgA B) IgG C) IgM D) IgE IgG is highly effective in neutralizing toxins due to its specificity and abundance. 9 / 10 Which antibody isotype is primarily involved in allergic reactions? A) IgG B) IgM C) IgA D) IgE IgE is responsible for Type I hypersensitivity and allergic responses. 10 / 10 Which immunoglobulin is present in the highest concentration in plasma? A) IgE B) IgM C) IgA D) IgG IgG accounts for about 75% of antibodies in plasma. Your score is The average score is 0% Description This video is part 2 of Acquired Immunity – Antibodies. All information in my immunology videos is sourced from: Book: Immunology, Eighth Edition by David Male, Jonathan Brostoff, David Roth, and Ivan Roitt Additional research: PubMed University lecture materials Antibodies: Plasma Proteins Where They Come From: B-cell (with BCR – IgG/IgD) binds to an antigen. Presents it on MHC II. APC activates a naïve Th cell through: TCR (CD4 and CD3) B7/CD28 interaction IL-4 receptor Naïve T helper cell secretes IL-2 (autocrine). Becomes an active Th2. Th2 helps activate B-cells through CD40L/CD40 and T cell receptor. Cytokine release: IL-4, IL-5, IL-8, IL-10, IL-2, IFN-γ, depending on the required antibody type. Components of an Antibody: Light Chain Heavy Chain Variable Part Constant Region Antibody Structure: Divided into: Fab (Fragment Antigen Binding) Fc (Fragment Crystallizable Region) Contains: VL (Variable Light) VH (Variable Heavy) CL (Constant Light) CH1, CH2, CH3 (Constant Heavy regions) Connected through disulfide bonds. Hinge region allows antibody motility. Antibody Domains: Variable Region: Antigen binding site CH1 Region: Determines allotype CH2 Region: Binds complement CH3 Region: Binds cells Variants of Chains: Light Chain: Lambda Chain, Kappa Chain Heavy Chain: Gamma Chain (IgG) Mu Chain (IgM) Alpha Chain (IgA) Delta Chain (IgD) Epsilon Chain (IgE) Functions of Antibodies: IgG: Structure: Monomeric (with subtypes) Plasma Amount: 75% Only antibody that crosses the placenta. Direct opsonization. Activates the complement system. Primary antibody in the secondary immune response (produced by memory B-cells). IgM: Structure: Pentameric (with a J-chain), Monomeric on B-cells. Produced by fetal immune system. Acts as the primary response antibody but does not provide memory. Complement activation. IgA: Structure: Dimeric (J-chain), Monomeric, Trimeric. Located in mucosal areas (gut, respiratory tract, urogenital tract). Secreted by alpha plasma cells. Bound to epithelial cells via poly-IgA receptors. Transported through endocytosis and released by proteolytic cleavage. Some microorganisms can cleave IgA. IgD: Structure: Monomeric. Plasma Amount: Under 1%. Localized on B-cell surfaces. IgE: Structure: Monomeric. Plasma Amount: Very low. Function: Binds to mast cells. Responsible for Type I hypersensitivity (allergic reactions). Increased levels in allergic diseases and parasitic infections. Differences Between Immunoglobulins: Idiotypic Differences: Differ in variable region. Isotypic Differences: Differ in constant region. Allotypic Differences: Genetic variation between alleles of the same constant gene. Transcript Introduction0:00in this video we’re gonna look at0:01antibodies antibodies are plasma0:04proteins known as immunoglobulins now toWhere do Antibodies Come From?0:07understand the different immunoglobulins0:09we have in our body I feel like it’s0:11most natural to know where they come0:13from first right so we got our b-cells0:16right here right chillin in the cortex0:17of the lymph node I’ll show you a scheme0:19later B cells have was called b-cell0:21receptors on the surface composed of0:23either IgG or IgM antibodies which are0:26membrane bound and a single transducer0:29as a heterodimer called IgA and RGB0:31those are those transmit the signal to0:34the nucleus when the IgG or IgM binds to0:37something right so now let’s imagine0:40this antigen right here was just catched0:42from the interstitial fluid from the0:44lymph vessel and then brought to the0:46cortex of the lymph node and it was0:48unlucky enough to accent the fit to the0:51membrane bound antibody on the surface0:53of the B cell it’s then gonna perform an0:55antigen B cell receptor endocytosis and0:58present a fragment of the antigen an MHC1:02class 2 molecule remember b-cells are1:04also antigen presenting cells – at the1:07same time at the rate Excel can also1:08phagocyte and the antigen and eventually1:11presented an MHC class 2 molecule1:13remember generating cells and B cells1:15are
Acquired Immune System
How the Acquired Immune System Work (Antigens, MHC) Official Links Instagram Youtube Jki-discord Notes & Illustrations Quizzes Summary & Transcript 📢 Currently, there is no PDF for this video.If you’re interested in having one, feel free to send an inquiry, and I may create it in the future. BUT! There’s a quiz available in the next tab. 12345678910 Acquired Immune System – QUIZ Test your understanding with 10 random multiple-choice questions from the question bank. You're in the preview mode. Note: All elements work correctly on the front end. 1 / 10 What defines the ability of an antigen to elicit an immune response? A) Complement activation B) Epitope diversity C) Immunogenicity D) Antigenicity Immunogenicity defines the ability of an antigen to cause an immune response. 2 / 10 What does MHC Class I primarily present to cytotoxic T cells? A) Viral RNA B) Bacterial toxins C) Exogenous peptides D) Endogenous peptides MHC Class I presents endogenous peptides to cytotoxic T cells. 3 / 10 What gene encodes the human MHC complex? A) Complement genes B) Immunoglobulin genes C) Cytokine genes D) HLA The HLA (Human Leukocyte Antigen) genes on chromosome 6 encode the MHC complex. 4 / 10 Which class of MHC molecules is involved in presenting antigens to T-helper cells? A) MHC Class I B) MHC Class III C) Cytokine genes D) MHC Class II MHC Class II presents antigens to T-helper cells to activate the immune response. 5 / 10 What happens to cytotoxic T cells upon activation by MHC Class I? A) Release cytokines B) Neutralize antibodies C) Activate macrophages D) Kill infected cells Cytotoxic T cells kill infected cells via perforin and granzyme after activation. 6 / 10 Which component of MHC Class I interacts directly with CD8+ cytotoxic T cells? A) β2 domain B) α2 domain C) α3 domain D) β1 domain The α3 domain of MHC Class I interacts with CD8+ cytotoxic T cells. 7 / 10 Which antigen is associated with bacterial capsules? A) O-antigen B) Vi-antigen C) H-antigen D) K-antigen The K-antigen is associated with bacterial capsules. 8 / 10 Which cytokine is essential for T-helper cell differentiation into Th1 cells? A) IL-4 B) IL-12 C) IL-10 D) TNF-α IL-12 is essential for the differentiation of T-helper cells into Th1 cells. 9 / 10 What triggers the activation of naïve T cells in lymph nodes? A) NK cell activation B) Antibody binding C) Antigen presentation D) Complement activation Antigen presentation by professional APCs via MHC molecules triggers T-cell activation. 10 / 10 What is the primary function of MHC Class III molecules? A) Encode complement proteins B) Induce fever C) Present antigens D) Activate B cells MHC Class III encodes complement proteins and cytokines, but does not present antigens. Your score is The average score is 0% Description This video is Part 1 of Acquired Immunity – Antigens and MHC. All information in my immunology videos is sourced from: Book: Immunology, Eighth Edition by David Male, Jonathan Brostoff, David Roth, and Ivan Roitt Additional research: PubMed University lecture materials Difference Between Innate and Acquired Immunity: Innate Immunity: Non-specific No immunological memory Attacks all agents equally Acquired Immunity: Specific defense Develops immunological memory Two Types of Acquired Immunity: Active Acquired Immunity: Developed through natural infection by microorganisms Induced through vaccination Outcome: Long-lasting immunity and antibody production Passive Acquired Immunity: Acquired by receiving antibodies (e.g., injection of antibodies) Transferred from mother to fetus through the placenta Outcome: Temporary immunity, as antibodies are used up over time Two Ways Adaptive Immunity Works: Humoral Immune Response: Antimicrobial Antiviral Antitoxic Cellular Immune Response: Attacks infected cells directly Antigens: Microorganisms Red Blood Cells Oncogenic Cells (Cancer Cells) Virus-Infected Cells Toxins and Venoms Proteins (Most immunogenic) Polysaccharides Lipoproteins Immunogenicity vs. Antigenicity: Immunogenicity: Ability to induce an immune response Antigenicity: Ability to bind to an antibody Epitopes: Multivalent antigen with different epitopes Multivalent antigen with repeated epitopes Continuous/Linear Epitopes Discontinuous/Conformational Epitopes Types of Antigens: Complete Antigen: Can induce an immune response Incomplete Antigen: Can bind to antibodies but does not trigger an immune response Thymus-Dependent Antigen: Requires T-helper cells for activation Thymus-Independent Antigen: Can activate B cells without T-helper cells Major Histocompatibility Complex (MHC): Human Leukocyte Antigens (HLA): MHC in humans Gene Location: Chromosome 6 (short arm) MHC Classification: MHC Class I: Includes HLA-A, HLA-B, HLA-C Present on all nucleated cells Structure: Alpha chain (1, 2, 3) and Beta chain 2 MHC Class II: Includes HLA-DR, HLA-DQ, HLA-DP, HLA-DM Present on professional antigen-presenting cells Structure: Alpha chains (1, 2) and Beta chains (1, 2) MHC Class III: Codes for complement proteins (C2, C4, Factor B) and cytokines MHC Class I Function: Recognized by: Natural Killer (NK) cells and Cytotoxic T cells (CD8+ T cells) Normal Function: Displays self-peptides on MHC I for immune surveillance Infected Cells: Present altered peptides on MHC I Recognized and destroyed by Cytotoxic T cells using Granzyme B and Perforin NK Cells: Recognize and kill cells with decreased MHC I expression MHC Class II Function: Antigen-Presenting Cells (APCs): Present foreign peptides to T-helper cells (CD4+ T cells) Leads to immune system activation Group Antigens: Enterobacteriaceae (E. coli, S. typhi): Different bacterial species share common antigens Antigen Types: O-Antigen: Lipopolysaccharides Vi-Antigen: Virulence factors K-Antigen: Capsular antigen H-Antigen: Flagellar antigen Transcript Introduction0:00hello and welcome to another video in0:02this video I’m going to talk about0:03acquired immunity now the immune system0:06uses two main strategies to defeat any0:08type of unwanted invaders one of them is0:10called the innate and other ones called0:12acquired so the innate immune system is0:14mainly present since birth and therefore0:16sometimes also called the natural immune0:19system they acquired however forms0:21during a person’s lifetime and it’s0:23therefore sometimes also called adaptive0:24now please don’t get this wrong this0:26baby also has some type of acquired0:28immune system I just put it there to0:29show you that you’ve always had innate0:32immune system ever since you were born0:33all right so let’s put this to practice0:36imagine there are three different types0:37of bacterias right the Indian immune0:40system is what we call nonspecific0:42because it’s going to attack all of0:43these