T Cell Development

Question 1

Location of T cell development

Answer 1

Thymus, then migrate to secondary lymphoid tissue

Question 2

T cells only recognize _____

Answer 2

peptide antigens

Question 3

T cell receptor immunoglobulin characteristics

Answer 3

membrane anchored
2 chains, each with a single constant and single variable domain
The two variables form the antigen-binding region

Question 4

Gamma/Delta T cell characteristics that differ from T cells

Answer 4

Not part of acquired immune response
Recognize lipid rather than peptide antigens 
Mature extrathymically
CD4 and CD8 negative 
found in mucosal epithelial of the gut

Question 5

CD3

Answer 5

signal transduction unit, targets the nucleus when T cell binds its cognate determinant
all 6 subunits involved in signaling

Question 6

ITAMS

Answer 6

on CD3, critical for initiation of signaling cascade.

Question 7

CD28

Answer 7

on T cells, binds to co-stimlator B7 that is expressed on antigen presenting cells when they encounter a pathogen

Question 8

FAS ligand

Answer 8

on T cells, binds 3 FAS protein and leads to apoptosis

Question 9

Adhesion molecules

Answer 9

Facilitate the interactions between T cells and antigen presenting cells, vascular endothelial cells, and potential target cells. All cell-to-cell interactions involving immune cells are initiated by adhesion molecules.

Question 10

CTLA-4

Answer 10

expressed on active T cells, has similar mechanism as CD28 but better binding affinity. serves as a “brake” and inhibits T cell activation and proliferation

Question 11

PD-1

Answer 11

binds PDL-1/2 and prevents T cell activation and proliferation, critical for preventing activation of self recognizing T cells

Question 12

cell types of the thymic cortex

Answer 12

macrophages
thymocytes
cortical epithelial cells

Question 13

cell types of the thyme medulla

Answer 13

macrophages
dendritic cells
hassalls corpuscles
thymocytes

Question 14

tingible macrophages

Answer 14

macrophages of the cortex that phagocytose thymocytes

Question 15

negative selection occurs in _____

Answer 15

the bulk of it in the medulla but some also in the corticomedullary junction

Question 16

pTalpha chain

Answer 16

an invariant chain that serves as a surrogate alpha chain so that a pre-T cell receptor complex can form. critical because beta chain develops first and is not stable when unbound

Question 17

positive selection of thymocytes

Answer 17

occurs in the cortex via cortical epithelial cells which display MHC class I and II molecules. T cells that are able to bind tightly are positively selected for while others undergo apoptosis/are engulfed by tangible macrophages

Question 18

negative selection

Answer 18

occurs mostly in the medulla, any cells that binds too tightly to MHC class I or MHC class II undergoes apoptosis

Question 19

AIRE

Answer 19

autoimmune regulator, transcription factor that drives expression of proteins not native to thyme function so that development of the T cells is not detrimental to the function of the thymus, also helps eliminate self-reactive T cells from repertoire

Question 20

Hassal’s corpuscles

Answer 20

produce TSLP cytokine and drives some self reactive CD4 T cells to differentiate into Treg cells instead of undergoing apoptosis

Question 21

Tregs

Answer 21

EFFECTOR CD4 T cells that help prevent self-reactive T cells from having detrimental affects in the peripheral tissues

Question 22

T/F Self reactive T cells are more likely to be positively selected for in the cortex

Answer 22

true, this is why negative selection is so important