Complement System Pathways (Classical, Alternative, MBL) + QUIZ | Immunology скачать в хорошем качестве

Complement System Pathways (Classical, Alternative, MBL) + QUIZ | Immunology

This video is part 3 of Innate immunity - Complement System (Humoral factors) Content: 0:00 Introduction 1:50 Classical Pathway 5:42 Alternative Pathway 7:23 Mannose Binding Lectin Pathway 13:07 What Does the a's Do? 14:39 QUIZ ------------------------------- 🫀 Join:    / @taimtalksmed   📷 Follow my IG:   / taimtalksmed   💝 Donation link: https://www.buymeacoffee.com/taimtalk... ------------------------------- All information in my immunology videos are from: Book: Immunology, Eighth Edition by David Male, Jonathan Brostoff, David Roth and Ivan Roitt Additional research in PubMed University lecture materials Mechanisms of complement system: Membrane Attack Complex Chemotaxis Opsonization Anaphylatoxins Classical Pathway: Antibody required (adaptive immune system) Step 1: C1q binds Step 2: C1r activates C1s Step 3: C1s cleaves C4, C2 Step 4: C4b and C2b works as C3 convertase Step 5: C3 convertase cleaves C3. Binds to surface as opsonin or binds to c3 convertase and works as C5 convertase Step 6: Membrane attack complex forms on gram negative bacteria. Alternative Pathway: Step 1: C3 undergoes spontanous cleavage in bloodstream. C3b bineds to surface of bacteria Step 2: Factor B binds Step 3: Protease (Factor D) cleaves Factor B into Bb Step 4: Properdin (Factor P) stabilizes the binding and form C3 convertase Step 5: Same steps as before from here Mannose Binding Lectin Pathway: Step 1: Active Macrophage release Interleukin 1, interleukin 6 and tumor necrotic factor alpha and work as Endogenic Pyrogens Step 2: Cytokines go to Hypothalamus and release Prostaglandins E2 (PGE2) which causes fever Step 3: IL-6 goes to liver and release acute phase proteins (C-reactive protein (CRP) and Mannose Binding Lectin (MBL)) C Reactive Protein (CRP) functions: Works as Opsonins and activate the classical pathway of the complement system Mannose Binding Lectin (MBL) pathway: Starts 1-2 days after infection: Step 1: MBL will bind to Mannose (monosacharide) on capsules and surface of fungi Step 2: Mannan binding lectin serine protease 1 (MASP-1) binds MBL and act as and enzyme. Step 3: same pathways as before !!!!Note!!! No MAC is formed on Capsules C4a, C5a and C3a works as: Anaphylatoxins: Increase permeability of capillaries and activate mast cells Chemotaxis: directs phagocytes to the area. Complement system can remove complex from the blood stream