T Cell Mediated Immunity- L9 Flashcards Preview

Immunology > T Cell Mediated Immunity- L9 > Flashcards

Flashcards in T Cell Mediated Immunity- L9 Deck (26):
1

Kinetics of a T cell response

Expansion occurs after exposure and number of antigen specific cells is optimal after 1-2 weeks

2

Potential fates of naive T cells

-Effector or memory cells
-Effector cells outnumber the memory cells
-These occur for both CD8 and CD4 naive T cells

3

Cells that prompt T cell activation

Dendritic cells. Take up antigens in skin and move to enter a draining lymphatic vessel. Bear antigen and wait for T cells in lymph node to respond.

4

Processing and presentation of antigen by dendritic cells

-Receptor mediated endocytosis of bacteria
-Macropinocytosis of bacteria or viruses
-Viral infection
-Cross presentation of exogenous viral antigens
-Transfer of viral antigens from infected dendritic cell to resident dendritic cell

5

Proteins controlling migration of naive T cells

-Selectins
-Integrins
-Chemokine receptors
-Control migration in and out of lymph nodes

6

Requirements for activating naive T cells

-Antigen recognition (occurs in lymph node)
-Costimulatory signal (B7/CD28)

7

B7/CD28

Important costimulatory signal for activating naive T cells

8

What if only recognition of antigen occurs?

-Unresponsiveness or anergy

9

What if only costimulation signal occurs?

-Trick question: this has no effect on T cells by itself

10

CD28 ligands

-B7-1 and B7-2
-Expression primarily limited to APCs
-B7-1 (CD80) absent from unstimulated cells
-B7-2 (CD86) is constitutively expressed at low levels on unstimulated dendritic cells and blood monocytes
-B7-2 is the major initial ligand and B7-1 sustains T cell activation

11

CD28 independent responses

-In the presence of a strong first signal, CD-28 mediated co-stimulation is not required
-CD28 costimulation is not required for effector and memory T cells

12

IL-2

Drives proliferation and differentiation of activated naive T cells. Causes the expansion of a specific population of T cells due to autocrine production of IL-2

13

TH1 cells

-Class of CD4 T cell
-IL-2 cytokine
-Activates macrophages

14

TH17 cells

-Class of CD4 T cell
-Enhance neutrophil response

15

TH2 cells

-Class of CD4 T cell
-Activate cellular and antibody response to parasites

16

TFH cells

-Class of CD4 T cell
-Follicular helper cell
-Activate B cell maturation

17

T reg cells

-Class of CD4 T cell
-Suppress other effector T cells

18

CD40 ligand expression

Critical to the ability of CD4+ T cells to activate other cells

19

Lupus

Overexpression of CD40

20

IFN-gamma and IL2 exposure induces

TH1 cells

21

IL4 and IL10 exposure induces

TH2 cells

22

Activation of CD8 T cells

-Makes IL2 to drive its own proliferation and differentiation
-Can also be driven by IL-2 produced by CD4 T cells

23

Granule exocytosis

-CD8 T cells perform it
-Fast killing
-Predominant pathway
-Granzymes (granzyme B cleaves pro-caspases) and perforin (perforin creates holes in membranes)
-Induces apoptosis in target cells through caspase activation and mitochondrial damage

24

Expression of cell surface TNF-family effector molecules

-CD8 T cells
-Slow killing
-Membrane TNF, lymphtoxin, Fas ligand, Trail

25

Secretion of soluble toxic cytokines

-CD8 T cells
-Slow killing
-TNF and interferon-gamma

26

T cell inactivation

-CTLA-4 competes for B7
-Inhibitory receptor for B7
-Binding to B7 leads to anergy
-Also inactivation can be impacted by: Elimination of Ag or other stimuli, T reg cells, or killing by immunoregulatory cells