Cellular Immunity Flashcards Preview

Foundations Test 4 > Cellular Immunity > Flashcards

Flashcards in Cellular Immunity Deck (22):
1

How are antigens taken to lymph node

When there is injury, dendritic cells take up and move to lymph node via lymphatic system

2

Nonbacterial vs bacteria engulfment by macrophage

Bacteria - PRRs stimulated, B7 expression induced, signal 2 delivered, T cells activated

3

3 signals

Activation - this is MHC/TCR interaction with CD4 or CD8

Survival - This is coreceptor B7 interacting with B7

Differentiation - production of cytokines from APC to the T cell

4

Dendritic cell in tissue vs. lymph node

In tissue - highly phagocytic, lower MHC expression, B7 not expressed, Ag presentation low

5

Where do lymph nodes receive lymphocytes?

From bloodstream and affarent lymphtics (coming from other lymph nodes)

6

Those T cells that don't have correct TCR will

Leave through efferent lymphatic vessel to next lymph node

7

T cells that do have correct TCR

Will stay in lymph node to proliferate

8

How do naive T cells enter secondary lymphoid tissues?

Non-specific cell adhesion molecules
Diapedesis

9

once in the secondary tissues, what do naive T cells do?

Bind to APCs via integrins and Ig superfamily molecules...this allows TCR/MHC interaction

10

What is co-inhibitory mechanism

B7 from APC binds CTLA-4 on the T cell

CTLA-4 binds with higher affinity than CD28

11

pSMAC and cSMAC

pSMAC has adhesion molecules needed to attach T cell to Dendritic

cSMAC has CD markers and TCR

12

TCR signaling leads to which TFs

NFAT, NFkB, and AP-1...leads to IL-2 transcription

13

Cyclosporine A

Block NFAT activation

14

Naive T cell TCR vs. mature

Naive - has gamma and beta subunit but not alpha...binds IL-2 with lower affinity

15

End result of IL-2 binding

Secretion of more IL-2 and porliferation

16

CD4 helper T differentiation

All these from dendritic cells

IL12 - Th1 - Cytotoxic
IL4 - Th2 - humoral
IL23 - Th17 - Inflammation
TGFB - Treg (tones down T cell response)

17

Antigen-specific T cell locations

Exposed and trapped in lymph node for a period of time where they won't be found in efferent lymph

18

CD8 (CTL) cells

Need CD3, CD8, alpha, beta, and T cell to work

Positive and negative selection in thymus

Clonal proliferation...helped by CD4s that secrete IL-2

19

CTL mediated killing

Rapid
Cell-cell contact
Apoptosis of target
Killer T can affect multiple targets
Bystanders unaffected

20

3 steps to CTL killing

Target cell binding
Programming target for lysis (Ca dependent)
Death

21

Perforin

Aids in delivering contents of granules into the cytoplasm...forms pores allowing passage of granzyme

22

Granzyme

Serine proteases that activate apoptosis in the cytoplasm of target cell