L6

Question 1

CD25

Answer 1

Part of the IL-2 receptor, essential for thymocyte survival and proliferation during T cell development

Question 2

Notch signaling

Answer 2

Directs thymic progenitors toward T cell lineage commitment

Question 3

TCF1

Answer 3

Transcription factor critical for TCR gene rearrangement and _-selection checkpoint in T cell development

Question 4

GATA3

Answer 4

Transcription factor important for CD4+ T cell lineage commitment

Question 5

Pre-TCR

Answer 5

Checkpoint receptor ensuring successful TCR _-chain rearrangement before _-chain recombination

Question 6

Positive selection

Answer 6

Process in the thymic cortex where T cells that recognize self-MHC moderately are selected for survival

Question 7

Negative selection

Answer 7

Process in the thymic medulla where T cells binding strongly to self-antigens are deleted to prevent autoimmunity

Question 8

Regulatory T cells (Tregs)

Answer 8

T cells that suppress immune responses, often arising during negative selection in the thymus

Question 9

CD28

Answer 9

Co-stimulatory molecule on T cells binding to B7 on APCs, necessary for full T cell activation

Question 10

ZAP-70

Answer 10

Kinase involved in T cell receptor signaling during activation

Question 11

Signal 2

Answer 11

Co-stimulatory signal preventing T cell anergy and promoting activation via CD28-B7 interaction

Question 12

Th1 cells

Answer 12

Differentiated CD4+ T cells involved in cell-mediated immunity, driven by IL-12 and T-bet

Question 13

Th2 cells

Answer 13

Differentiated CD4+ T cells involved in humoral immunity, driven by IL-4 and GATA3

Question 14

Th17 cells

Answer 14

Differentiated CD4+ T cells producing IL-17, involved in inflammation and autoimmune responses

Question 15

Tfh cells

Answer 15

Follicular helper T cells supporting B cell maturation and antibody production, regulated by Bcl-6

Question 16

Tregs

Answer 16

Regulatory T cells promoting immune tolerance, driven by TGF-_ and Foxp3

Question 17

Memory T cells

Answer 17

Long-lived T cells providing faster responses upon re-exposure to antigens

Question 18

Effector memory T cells (Tem)

Answer 18

Reside in peripheral tissues and respond rapidly to re-infection

Question 19

Central memory T cells (Tcm)

Answer 19

Reside in lymphoid organs and have high proliferative potential

Question 20

Perforin

Answer 20

Protein used by cytotoxic T cells to form pores in target cell membranes

Question 21

Granzyme

Answer 21

Protease entering target cells through perforin pores to trigger apoptosis

Question 22

Caspase-3

Answer 22

Executioner caspase activated during apoptosis by cytotoxic T cells

Question 23

PD-1

Answer 23

Immune checkpoint receptor inhibiting T cell activation when bound to PD-L1 or PD-L2

Question 24

CTLA-4

Answer 24

Immune checkpoint receptor competing with CD28 for B7 binding, suppressing T cell activation

Question 25

Anergy

Answer 25

State where T cells become unresponsive to antigen due to lack of co-stimulatory signals

Question 26

Thymic selection

Answer 26

Process ensuring T cells are MHC-restricted and self-tolerant through positive and negative selection

Question 27

Checkpoint inhibitors

Answer 27

Drugs targeting PD-1 or CTLA-4 to enhance T cell activation against tumors