Antibacterial Responses Flashcards
What are the features of a bacterial infection?
Live and replicate in extracellular spaces
Disease (generally) caused by the toxins
What are the key steps in infection?
Entry
invasion and colonisation of host tissue
Evasion of immunity
Tissue damage
What are the two types of defensins?
Alpha
Beta
What are alpha defensins secreted by?
Neutrophils and paneth cells
What are beta defensins secreted by?
Broad range of epithelial cells
What is complement?
Serum and cell surface proteins that interact with one another to generate products that eliminate extracellular bacteria
What are the complement pathways?
Classical
Lectin
Alternative
What activates the classical pathway?
Antibodies
What activates the lectin pathway?
Carbohydrates
What activates the alternative pathway?
Specific PAMPs
What does complement cause?
Inflammation, lysis and opsonisation
What is it called when neutrophils phagocytose gut bacteria?
Neutrophils extracellular traps
How do toxins work?
Binds to cellular receptors
Endocytosis of toxin/receptor complexes
Dissociation of toxin to release active chain, poisoning cell
How is the complement cascade triggered?
IgM bound to the surface of a bacterium binds to a complement component
Causes the bacterial cell surface to be Coated in C3b, facilitating phagocytosis
What does the MHC class II pathway present?
Bacterial antigens derived from extracellular infections to helper T cells
