Lecture 13 T cell mediated immunity

Question 1

Why do we need adaptive immunity?

Answer 1

• immunological memory, specificity, flexibility, respond to evolution, efficiency

Question 2

Why are T cells necessary as part of adaptive immunity?

Answer 2

• induce B cell response
• cell mediated response (cancer)

Question 3

T cell targets given antigen only in the presence of ____

Answer 3

self

Question 4

cytotoxic T cells recognize ___ aa peptides in context of MHC I (genes: ____)

Answer 4

8-10; AB&C

Question 5

helper T cells recognize ___ aa peptides in context of MHC II (genes: ___)

Answer 5

12-25; DP, DM, DO, DQ, DR

Question 6

What are the three developments of the immune response?

Answer 6

1. nonspecific, innate
2. central (priming) phase
3. T cell effector phase

Question 7

The central (priming) phase occurs in _______ and T cells are primed by ___

Answer 7

central lymph node; APC

Question 8

The T cell effector phase (______ _______) is directed at _______ and makes the area inflammatory

Answer 8

secondary activation; target tissue

Question 9

T helper cell types

Answer 9

1, 2, 17, follicular

Question 10

Priming stage starts by initial ___ recognition of antigen by _____

Answer 10

TCR; professional APC

Question 11

The priming stage is _____

Answer 11

afferent

Question 12

The effector stage refers to ______ recognition by effector T cells. It requires signal __

Answer 12

invader/source; 3

Question 13

T cell priming occurs in the _______ which is why there is ______ after vaccination

Answer 13

draining lymph node; swelling

Question 14

T cells enter lymph node cortex via _____ and meet up with DCs in _______. DCs enter via lymphatics.

Answer 14

high endothelial venules;
paracortex

Question 15

Describe how T cells are trafficked into draining lymph node

Answer 15

1. rolling (L-selectin binds CD62L)
2. activation by CCR7
3. adhesion via LFA-1 and ICAM (integrins)
4. diapedesis CCR7 responds to CCL21, CCL19, CXCL12

Question 16

_____ is a lipid chemoattracant and would cause the T cell to get out of the lymph node. ____ downregulates this factor so they are stuck. This is an activation marker, showing they’ve been activated by DC.

Answer 16

S1PR1; CD69

Question 17

If T cells are not activated by DCs, they will not exhibit ____, so they will

Answer 17

CD69; GTFO

Question 18

DCs present to ____ T cells

Answer 18

naive

Question 19

Macrophages and B cells present to _______ T cells. The ____ results in function (autophagic/antibody production)

Answer 19

effector;
CD40L

Question 20

______ discovered DC

Answer 20

Ralph Steinmann

Question 21

______ DC produce buckets of IFN-alpha

Answer 21

plasmacytoid

Question 22

Mature DCs express more

Answer 22

CCR7, CD80/86, CD40, MHC, CD25, ICAM

Question 23

DCs can pick up antigens via

Answer 23

receptor-mediated endocytosis, macropinocytosis, viral infection, cross presentation after uptake, or transfer from incoming DC to resident

Question 24

TLR signaling induces _____ expression so that DCs migrate to the ________ upon maturation

Answer 24

CCR7; lymph node via draining lymphatics

Question 25

Resident DCs have a tendency to interact with ____ first. Migratory DCs tend to interact with ___ first

Answer 25

CD8+; CD4+

Question 26

T cell: APC binding
Supermolecular activation complex (SMAC)

Answer 26

first LFA-1:ICAM (pSMAC)
then TCR binds MHC/antigen (cSMAC), signals LFA-1 to keep binding,
CD8/4 facilitate binding, CD28 binds CD80/86 (cSMAC)

Question 27

What happens during polarization of T cell?

Answer 27

CD45 moves distal (dSMAC)
TCR, CD28 closes in

Question 28

Signal 1

Answer 28

TCR: MHC
tells the identity of the problem maker

Question 29

Signal 2

Answer 29

CD28: CD80/86
impacts survival of T cell and magnitude of activation/response
tells how dangerous the problem is

Question 30

Signal 3

Answer 30

cytokines to TCR,
tells this is what you are supposed to do

Question 31

What occurs in signal 2 only (no signal 1)

Answer 31

no effect

Question 32

What occurs in signal 1 only (no signal 2)

Answer 32

anergy/deletion of T cell (decreased TCR signaling through induction of GRAIL and activation of Cbl)
so that you don’t kill yourself

Question 33

An activated T cell expresses ____, the alpha chain that increases affinity for ____ so the cell is now susceptible as an autocrine factor

Answer 33

CD25; IL-2