1.3 host immune response

Question 1

barriers of innate system?

Answer 1

urination
- sterile bladder

mucocilliary elevator
- protects airways

cough reflex
- protects airways

lysozyme
- antimicrobial enzyme in tears/saliva/breast milk
- attacks peptidoglycan of gram+

lactoferrin
- protein in milk competes with bacteria for iron

IgA
- Ab in bodily secretions
- clears antigens from intestinal lumen by blocking epithelial receptors
- entraps them in mucous

normal flora

Question 2

how does inflammation protect from pathogens?

Answer 2

vasodilation
- caused by vasoactive and chemotactic factors
- increase diameter and permeability

fluids accumulate

recruitment of neutrophils (enter tissue extravasation)

phagocytosis

Question 3

lymphoid system? primary vs secondary organs?

Answer 3

sites for immune cell generation, training, or sites of action

primary organs: mature (thymus, bone marrow)

secondary organs: activate (lymph nodes, spleen)

Question 4

adaptive system divisions?

Answer 4

humoral

cell-mediated

Question 5

role of humoral immunity?

Answer 5

mediated by Ab

eliminate extracellular pathogens

Question 6

role of Abs?

Answer 6

neutralization (bind + inhibit pathogen)

opsonization (mark for destruction)

complement activation (glycoproteins that enhance killing by binding Ab-bound bacteria)

Question 7

role of cell-mediated immunity?

Answer 7

mediated by T-cells mainly

Question 8

cytotoxic T-cells (CD8+)?

Answer 8

destroy compromized cells by recognizing foreign protein sequences on the cell surface

replicate to clear pathogen

once cleared, undergo contraction, leaving some too become memory cells

Question 9

mechanism of T-cell mediated immunity?

Answer 9

CD4+ helper T-cells binds MHC-II on AB-presenting macrophage

activates CD4+, release cytokines

B-cells and CD8+ cells activated

CD8+ interact with MHC-I on infected cells

produce granzymes and perforins

Question 10

role of helper T-cells?

Answer 10

activate + coordinate immune response

release cytokines to activate CD8+ and maximize bactericidal activity of phagocytes

Question 11

role of tregs?

Answer 11

immunosuppressive cells

suppress CD4+, CD8+, B-cells, dendritic cells

Question 12

tregs in atherosclerosis treatment?

Answer 12

tregs inhibit dendritic cells (prevents T-cell activation in disease)

inhbit pro-atherogenic T-cells

promote anti-inflammatory macrophages

suppress activation of endothelial cells in blood vessel

inhibit formation of foam cells (macrophage ingesting LDL)

reduce LDL and VLDL

Question 13

what is colonization?

Answer 13

pathogen attaches to host mucosal surface and grows

mau cause infection based on virulence factors