L19 - Antibacterial Responses Flashcards
Describe some mechanical innate immune system defence mechanisms
Perspiration
flow of fluid in GI tract, Resp tract, UG tract, and eyes.
mucus, saliva, cilia, epithelial cells, urine, tears
Describe some chemical innate immune system defence mechanisms
sebum, acidity and enzymes in GI tract, lysozyme is nasal secretions
Acidity in vaginal and spermine secretions
Lysozyme in tears
Describe some microbiological innate immune system defence mechanisms
Normal flora of the skin, GI, UG, Resp tract and eyes
Describe the role of Anti-bacterial peptides?
Anti-microbial peptides capable of killing by penetrating microbial membranes thus disrupting their integrity.
They are active against bacteria, fungi and many enveloped and non-enveloped viruses.
There are two types: 𝛂-defensins and β-defensins.
What are the 2 types of Anti-bacterial peptides and how are they secreted?
There are two types: 𝛂-defensins and β-defensins.
𝛂-defensins are secreted mainly by neutrophils and by Paneth cells
β-defensins are secreted by a broad range of epithelial cells, in particular, those in the respiratory tract, the skin and the urogenital tract.
What is the Complement System and its 3 pathways?
Key effector function of the humoral response.
Serum and cell surface proteins that interact with one another to generate products that eliminate extracellular bacteria
3 pathways:
CLASSICAL - antigen-antibody immune complexes
LECTIN - PAMP recognition by lectins
ALTERNATIVE PATHWAY - Spontaneous hydrolysis/pathogenic surfaces
Describe the role of TLRs and how they function?
Toll-like receptor
Capable of detecting componenents of bacteria like bacterial lipopeptides, bacterial peptidoglycan, flagellin
What does PAMPs and PRR interaction lead to?
phagocytosis and cytokines
How do Neutrophils deal with bacteria?
Phagocytosis and degranulation of granules- intracellular killing of bacteria
Phagocytosis and oxidative burst kills the bacteria
Neutrophils can also kill bacteria phagocytosing bacteria - Neutrophils Extracellular Traps (NETS)
Describe the neutralisation of toxins?
- toxin binds to cellualr receptors
- endocytosis of toxin receptor complex
- disassociation of toxin to release active chain whoch poisons cell
- antibody protects cell by blocking binding of toxin
What are the Antibacterial qualities of IgM?
- Neutralisation
- Activation of complement system
What are the Antibacterial qualities of IgG1?
- Neutralisation
- Opsinisation
- Sensitisation for killing by NK cells
- Sensitisation of Mast cells
- Activation of complement system
What are the Antibacterial qualities of IgG2?
- Neutralisation
- Activation of complement system
What are the Antibacterial qualities of IgG3?
- Neutralisation
- Opsinisation
- Sensitisation for killing by NK cells
- Sensitisation of Mast cells
- Activation of complement system
What are the Antibacterial qualities of IgG4?
- Neutralisation
- Opsinisation
