Local Immunity/T Cell Memory

Question 1

Difference in CD4 and CD8 Effects on Intracellularly Infected Cells

Answer 1

CD4s interact with and induce death, CD8s kill directly

Question 2

CD4 TH1 Differentiation

Answer 2

Dendritic cells release IL-12 and bind NK cells and induce them to release IFNgamma
These two activate transcription of T-bet in naive CD4 Ts, causing differentiation into TH1

Question 3

4 Effects of CD4 TH1s to Coordinate Host Response (8 total molecules)

Answer 3

Act on progenitor cells in marrow to increase macs/DC #s - IL-3, GM-CSF
Recruit macs - CCL-2
Activate macs - TNFalpha/beta, IFNgamma
Activate endothelial cells - TNFalpha, CCL-2

Question 4

TH1 CD4 Activation of Macs (3)

Answer 4

Come together via MHC II - TCR binding
CD40L on T binds CD40 on mac
**IFNgamma from T binds R on mac, stimulating killing of intravesicular activity

Question 5

3 Effects of Activation in Macs

Answer 5

Better phagolysosome fusion
Increase in lysosomal enzyme transcription
Increase in microbicidal agents like ROS and proteases

Question 6

3 Components of Successful Immune Response

Answer 6

Clears infection
Temporarily strengthens defenses to prevent reinfection
Establishes long term memory

Question 7

3 Differences b/w T effector memory and T central memory cells

Answer 7

Location: inflamed tissues and secondary lymphoid tissues
Cell Surface Marker: CD62L low/high
Purpose: effect molecules like cytokines/toxins and help B cells produce Ig via CD40L

Question 8

5 Cell Surface Marker Differences b/w TM and TN/TE (& one other difference)

Answer 8

Lower CD62L
Higher CD44 adhesion (not naive)
Higher CD45RO than CD45RA (TN), tyrosine phosphatase
Higher bcl-2 - antiapoptosis
Higher CD127, alpha chain of IL-7R
Also require low costimulation, whereas TN require strong and TE require none

Question 9

2 Methods to Maintain TM Pool

Answer 9

Antigen exposure for proliferation

Slow, steady proliferation via IL-15 and IL-7 without Ag exposure

Question 10

Delayed Type Hypersensitivity

Answer 10

Used to test previous exposure like PPD TB test

Inject Ag w/ adjuvant, wait a few days, Th1 eff/mem release cytokines and cause inflammation

Question 11

2 Responses to M. Leprae (and major point)

Answer 11

Th2 CD4s - Ab response, ineffective, disseminated infection

Th1 CD4s - mac activation, localized infection