Innate Immunity

Question 1

Key Cell types (6)

Answer 1

Monocytes, neutrophils, mast cells, basophils, eosinophils, Nk cells

Question 2

Respiratory burst steps (transient increase in oxygen consumption by the cell) (results in ROS)

Answer 2

(1) Increased O2 uptake
(2) Increased catabolism of glucose to NADH (via NADH oxidase/phagocyte oxidase)
(3) Release of superoxide anions

Question 3

Methods of Neutrophil killing (3)

Answer 3

ROS (via respiratory burst), NOS (generated by inducible Nitric Oxide Synthase), NETs (extrusion of nuclear material, DNA and histones - makes a net to which antimicrobial proteins are bound)

Question 4

Complement System Pathways and Triggers

Answer 4

Classical pathway (antigen-antibody complexes), MBP lectin (lectin binds pathogen surface), Alternative pathway (pathogen surface)

Question 5

Functions of the complement system and components involved

Answer 5

proinflamm mediators (C5a and C3a), MAC assembly (C5a-9), Opsonisation of pathogens (C3b mainly)

Question 6

Opsonic Macrophage Receptors (2)

Answer 6

FcRs (Fc receptor - classified based on the type of antibody they recognise)
CR3 - complement receptor - binds to C3b when bound to the surface of foreign cells

Question 7

Non-opsonic receptors (TLRs) (3 functions)

Answer 7

• 10 mammalian, TLR5 - bacterial flagellin, TLR-4 - LPS, TLR-3 - dsRNA (i.e. viruses)

Question 8

NON TLR NON OPSONIC RECEPTORS (2)

Answer 8

Scavenger receptors (CD36) and Lectins (Dectin-1 - beta-glucan - major component of fungal cell walls)