Host Defense

Question 1

Granulomas are formed due to which type of pathogen?

Answer 1

Intracellular microbes not dying

Macrophages wall off bactaria - bad if happens in lung, can damage tissue

Question 2

Deleterious effects of immune system from viruses

Answer 2

Autoimmune diseases (Molecular Mimicry)
Hep B - induces CTL's to destroy hepatocytes

Question 3

How do extracellular bacteria cause damage?

Answer 3

Production of toxins and cause inflammation

Question 4

Innate response to extracellular bacteria

Answer 4

Phagocytosis by neutrophils, monocytes, macrophages

Peptidoglycan or LPS - cause alternative complement pathway activation - lyse/opsonize

Question 5

In septic shock, what do marophages release?

Answer 5

TNF and IL-1

Question 6

Best way to fight off intracellular bacteria?

Answer 6

Innate Immunity:
Macrophages release IL-12, causes NK cells to release INF-gamma

Adaptive Immunity required
T cells get activated and release INF-gamma
Finishes the job!

CTL’s can be activated if bacteria present in cytosol

Question 7

Deleterious immune effects against intracellular bacteria

Answer 7

Granuloma formation - surrounded by T cells

Question 8

Immune response to viruses

Answer 8

Innate:
Cells release INF-1 (alpha/beta)
Viruses downregulare MHC-I
Both Activate NK cells

Adaptive
Early - Only used if already have Ab - opsonize, prevent it from binding, activate complement

Established - CTL’s lyse virus-infected cells (endogenous antigen - MHC-I)

Question 9

Proper immune response to fungi

Answer 9

Requires both humoral and cell-mediated

Neutrophils - phagocytose

Th1

Don’t know if Ab do anything against fungi