adaptive immunity and T cells 1 Flashcards
1
Q
what is cell mediated immunity
A
coordinated by T cells and protects against intracellular and extracellular pathogens
2
Q
what subunits can T cells possess
A
γδ or αβ TCR
3
Q
what are the steps in lymphoid cell ontogeny
A
1) pro-t cell migrates to thymus
2) early thymocytes do not express cell surface markers
3) common thymocytes express TCR, CD3,CD4 and CD8
4) thymic selection occurs to eliminate auto reactive cells - mature T cells loose ability to express certain markers
4
Q
what do mature T cells do
A
- secrete cytokines that determine immune response
- target cells depending on class of pathogen
- express costimulator molecules which bind to CD80 and CD86
5
Q
what expresses costimulatory molecules
A
dendritic cells
6
Q
what do TH1 cells do
A
- secrete IFNy
- intracellular bacteria - Leishmania and micro bacteria
6
Q
what do TH2 cells do
A
- secrete IL-4, IL-5 - act on bone marrow
- secrete IL-14 - act on goblet cells
- parasitic infections
7
Q
what do TH17 cells do
A
- secrete IL-17 - acts on stromal cells
- secrete IL-22 - acts on epithelial cells
- extracellular bacteria
