T Cell Immunity Flashcards Preview

Term 3: Immunology/Pathology > T Cell Immunity > Flashcards

Flashcards in T Cell Immunity Deck (24):
1

What are the two types of T cell receptors?

-alpha-beta

-gamma-delta

*T-cell will have one or the other, not both

2

What is the most common type of T cell receptor?

-alpha-beta

3

What are CD4 and CD8 with respect to T cell receptors?

-co-receptors

4

What do alpha-beta receptors recognize?

BOTH the presented peptide and the MHC molecule

5

How do T-cell receptors signal the T cell nucleus?

-CD3 complex

-TCRs cluster together

-CD3 recruits kinase enzymes to activate nucleus & proliferation

6

What do CD8 and 4 do?

clip onto either MHC I (CD8) or MHC II (CD4)

=focus the attention of Th and CTL cells on the proper MHC molecule, stabilizes connection

-strengthen TCR signal to the nucleus

7

What acts as the costimulatory signal to activate naive T cells?

-B7

**on B cells and dendritic cells

8

What happens when CD40L on the Th cell binds to the CD40 receptor on the dendritic cell?

-dendritic expression of MHC and B7 will be increased

-dendritic cell's lifespan is also extended

9

What do helper T cells do once they are activated?

-parts ways with APC

-proliferate

-produce large amounts of IL-2

10

What is a brief sequence of T cell activation?

-Adhesion molecules mediate weak binding between Th and APC

-TCR’s engage their cognate antigen presented by APC

-Receptor engagement strengthens the adhesion

-Upregulates CD40L expression on the Th cell

-CD40L binds to CD40 on the APC

-Stimulates expression of MHC and co-stimulatory molecules on APC

-When activation is complete the Th cell proliferates

-This proliferation produces clones of helper T cells which recognize the invader

11

How do helper T cells enhance the action of Cytotoxic T Lymphocytes?

-Help CTLs kill efficiently

-Th also help CTL's become long-lived

-helps CTL's generate memory T cells

-Provide IL-2 needed for CTL's to proliferate (controls strength of response)

12

What interleukin is produced by activated dendritic cells once they reach a lymph node?

IL-12

13

What does IL-2 from T helper cells do?

-recharges natural killer cells

-stimulates growth of Cytotoxic T lymphocytes, NK cells, and Th1 cells

14

What do Th1 cytokines do?

-instruct the innate and adaptive systems to produces cells and antibodies against both viruses and bacteria

-IFN-gamma tells B cells to switch to IgG3

15

Which cytokines are produced by Th2 cells?

-IL-4

-IL-5

-IL-13

16

What does IL-4 do?

-stimulates production of Th cells

-stimulates B cell growth

-Influences production of IgE antibodies (good against parasites)

17

What does IL-5 do?

-encourages B cells to produce IgA

* useful in protecting GI tract

18

What does IL-13 do?

-stimulates production of mucus in GI system

*protects against pathogen invasion

19

What do Th0 cells do?

-remain "unbiased" when first activated, retaining the ability to produce a wide range of cytokines

20

Do cytokines act locally or systemically?

Locally

21

What produces perforin and what does it do?

-produced by cytotoxic T cells

-binds to cell membranes and drills holes in them

22

What does a cytotoxic T cell use to kill its foes?

-perforin

-Granzyme B (triggers Apoptosis)

-FasL (binds Fas, triggers Apoptosis)

23

What cytokines are produced by Th1 cells?

-TNF

-IFN-gamma

-IL-2

24

What do Th17 cells do?

Fight fungus