Uploaded March 2019 | Updated September 2026, 1 week ago
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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
--------------------------------------------------------------------------------
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
--------------------------------------------------------------------------------
TLR dimerization: ncbi.nlm.nih.gov/pmc/articles/PMC3075535
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
🌐 Website: taimtalksmed.com
🫀 Help keep this content free: youtube.com/channel/UCEr7pkSXVsHcBLLBcJAGV-Q/join
🔬 Get 10% off anatomy lab models (affiliate link): https://anatomywarehouse.com?aff=34
📲 Other Links:
Instagram: instagram.com/taimtalksmed
Discord: discord.com/invite/DENMUpS8ey
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
--------------------------------------------------------------------------------
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
--------------------------------------------------------------------------------
TLR dimerization: ncbi.nlm.nih.gov/pmc/articles/PMC3075535
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
