Chapter 5 T Cell Mediated Immunity- Activation of T cells Flashcards
describe the induction and effector phases of cell mediated immunity
- induction of response
- antigen recognition in lymphoid organs
- T cell expansion and differentiation
- Differentiated effector T cells enter circulation
- migration of effector T cells and other leukocytes to site of antigen
- effector T cells encounter antigens in peripheral tissues
- activation of effector T cells
- T cells effector functions
what are the effector functions of T cells
- leukocyte activation: phagocytosis and killing of microbes
- CTL killing of infected cell
what are the steps in the activation of T lymphcytes
-antigen recognition
- cytokine secretion and cytokine receptor expression
- proliferation
- differentiation
- effector functions
what are the effector functions of T lymphocytes
- CD4+: activation of macrophages, B cells, other cells
- CD8+: killing of infected “target cells”; macrophage activation
what do adhesion molecules do
stabilized T cells binding to APCs
what is LFA-1
an integrin protein
what is ICAM-1
a ligand
explain the role of costimulation in T cell activation
activation of APCs by microbes causes an innate immune response using B7 and CD28 causes T cell proliferation and differentiation
what are inhibitory receptors necessary for
limiting/terminating immune responses
what are the inhibitory receptors
- B7 and CD28
APCs that engulf virus infected cells and are infected themselves will have antigens presented by _______
both class I and II MHC molecules
in the case of APCs that engluf virus infected cells and are infected themselves which is activated first: CD4+ or CD8+
CD4+ activates the CD8+ T cell
what is calcineurin neutralized by
cyclosporine
what is Akt, mTOR neutralized by
rapamycin
what is the principal function of IL-2
survival and proliferation of antigen specific T cells
describe the secretion of cytokines and expression of cytokine receptors
- T cell activation by antigen + costimulator
- secretion of IL-2
- expression of IL-2Ralpha chain; formation of high affinity IL-2Ralphabetagamma complex
- IL-2 induced T cell proliferation
Which T cell is produced in higher quantity following infection
CD8+
Describe the development of effector CD4+ T cells
- Tfh cells remain in lymphoid organ, migrate into follicles
- help B cells produce high affinity antibodies
- Tfh cells become effector T cells and antibodies enter circulation and go to sites of infection
- elimination of microbes
what do CD4+ cells activate
macrophages and B lymphocytes
what are the effector functions of macrophages and B lymphocytes in cell mediated immunity and humoral immunity
- cell mediated: macrophages activate and kill phagocytosed microbes
- humoral: secretion of antibodies with enhanced abilities to neutralize and eliminate antigens
what kind of receptor is L-selectin in naive T cellsand what is its ligand
selectin
- L-selectin ligand
what kind of receptor is LFA-1 in naive T cells and what is its ligand
-integrin
-ICAM-1
what kind of receptor is CCR-7 in naive T cells and what is its receptor
chemokine receptor
- CCL19 or CCL21
what kind of receptor is E and P selectin ligand and what is its ligand in activated T cells
selectin
- E or P selectin ligand
what kind of receptor is VLA-4 and what is its ligand on activated T cells
-integrin
- ICAM-1 or VCAM-1
what kind of receptor is CXCR3 and what is its ligand on activated T cells
-chemokine receptor
- CXCL10
where do effector T lymphocytes migrate
peripheral tissue
what receptors are activating
CD28 and ICOS
what T cell receptors are inhibitory
CTLA-4 and PD-1
what are the transcription factors involved in genes for T lymphocytes
NFAT
NF kappaB
AP-1
