9.1 Immunity to Intracellular Pathogens

Question 1

Name 2 advantages of surviving within the phagocyte

Answer 1

continuous supply of nutrients

shielded from extracellular immune response

Question 2

Name 1 disadvantage with surviving in the phagocyte

Answer 2

need to overcome innate immune responses

Question 3

How do phagosomal pathogens survive?

Answer 3

replicate in early phagosome compartment

avoid ocntact with lysosome contents

Question 4

How do pathogens survive in the cytosol?

Answer 4

they escape and replicate within the cytosol, avoiding contact with lysosome contents

Question 5

What innate mechanisms are used to kill intracellular pathogens? (6)

Answer 5

acidification
toxic oxygen - derived stuff
toxic N - derived stuff
antimicrobial peptides
enzymes
competitors

Question 6

Name an antimicrobial peptide

Answer 6

defensin

Question 7

What parts of the CD4 Th1 cell activates macrophage?

Answer 7

IFN - gamma

CD40 ligand

Question 8

what part of CD4 Th1 stimulates apoptosis?

Answer 8

Fas ligand

Question 9

What part of CD4 Th1 stimulates T cell proliferation?

Answer 9

IL-2

Question 10

What parts of CD4 Th1 stimulates bone marrow macrophage differentiation?

Answer 10

IL - 3

GM - CSF

Question 11

What parts of CD4 Th1 stimulate endothelial macorphage binding and extravasation?

Answer 11

TNF-alpha

LT-beta

Question 12

What is CCL2 important for?

Answer 12

chemotaxis

Question 13

What are CD4 Th1 cells primed by?

Answer 13

dendritic cells via MHC class II

Question 14

What activates macrophage?

Answer 14

primed CD4 Th1 cells

Question 15

what does Th1 activated macrophae increase the expression of?

Answer 15

MHC class I + II
CD40
CD80 / CD86 amplification

Question 16

How are cytosolic - resident bacteria killed?

Answer 16

antigen in host cell presented on MHC class I
CD8 T cells do the killing

Question 17

What baceria causes Tb?

Answer 17

Mycobacterium tuberculosis

Question 18

Is Tb gram + or -?

Answer 18

+

Question 19

What feature of Tb might effect drug permeability?

Answer 19

complex lipid envelope

Question 20

What 3 innate phagocyte killing mechanisms are inhibited by TB?

Answer 20

ROS
RNS
phogosome : lysosome fusion

Question 21

What do we use to prevent TB?

Answer 21

Bacilllus Calmette - Guerin Vaccine (DCG)

70-80% effective against severe forms of TB

Question 22

What is one drawback to the BCG vaccine?

Answer 22

it is a live vaccine, so we don;’t give it to immunocompromised patients

Question 23

What are the 2 common causes of genetic predisposition to TB?

Answer 23

CD4 T cell defects (SCID)

Th1 cytokine or receptor defects (IFN gamma, IL12/23)