Врожденная иммунная система (Toll-подобные рецепторы, Фагоцитоз и Воспаление) - Иммунология

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This video is part 2 of Innate immunity - Cellular Factors (Toll-like Receptors, Phagocytosis and Inflammation)

Content:
0:00 Introduction
0:20 Toll-Like Receptors
4:45 Phagocytosis
12:40 Immune System's Role in Inflammation

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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
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TLR dimerization: https://www.ncbi.nlm.nih.gov/pmc/arti...

Toll Like Receptors:

Location:
Epithelial Cells of mucous membrane
Endothelial Cells
Macrophages
Dendritic cells
Neutrophils

Membrane bound TLR:
TLR 1/2 and TLR2/6:
Peptidoglycan/Lipotechoic acid
Lipoproteins
TLR 4:
Lipopolysaccharides
Fungal Mannan
Viral Envelope Protein
TLR 5:
Bacterial flagellin

Intracellular receptors:
TLR 3:
Double Stranded RNA from virus
TLR 7:
Single Stranded RNA
TLR 8:
Double stranded RNA from virus
TLR 9:
Unmethylated CpG islands

Toll Like Receptors trigger:
1. Release of cytokines (TNF, IL1 and IL12)
2. Chemokines (IL8)
3. Antiviral Cytokines (IFN a/b)

Phagocytosis:

Professional Phagocytes:
Neutrophils
Macrophages/Monocytes
Mast Cells
Dendritic Cells

Steps in Phagocytosis:
Step 1: Binding
Non specific surface receptors (Mannose Receptor, Toll Like receptor, CD14)
Indirect Opsonization (C3b)
Direct Opsonization: Fc receptor to antibody
Step 2: Engulfment
Pseudopods around bacteria
Step 3: Phagosome
Formation of phagosome
Step 4: Digestion
Oxygen Dependent digestion (Reactive Oxygen Species)
Oxygen independent digestion
Lysosome (Cell wall breakdown)
Enzymes (Proteolytic, Hydrolytic)
Antimicrobial Peptides (Defensins)
Acidic Reactions (Low pH)
Lactoferrin (Neutrophils)
Step 5: Antigen Presentation
Present on MHC class 1 or class 2
Or release digested bacteria to Interstitial fluid. It’s then absorbed by the lymph vessels to the lymph node

Active macrophage release cytokines:
Interleukin 8: Chemotaxis for Leukocytes
Interleukin 1: Activate T-Ly and Macrophages
Interleukin 6: Activate T- and B-Ly
TNF-a: Activate Endothelium
Interleukin 12: Activate Natural Killer cell

Interleukin 1, 6 and Tumor necrotic factor alpha: Endogenic Pyrogens (Cause Fever)
Goes to Hypothalamus to release Prostaglandins E2
Interleukin 6 goes to the liver to release acute phase proteins

Incomplete Phagocytosis:
Phagocytes can’t breakdown bacteria
Listeria: release Listeriolysin
Mycobacteria tuberculosis: catalase

Immune system in Inflammation:
Swelling (Due to increase permeability of blood vessel)
Pain (Due to diapedesis and edema pressing on pain receptors)
Heat
Redness