Major functions of T cells Flashcards
What do CD4+ T cells do?
Help B cells make Ab and produce cytokines to activate other immune system cells
What do CD8+ T cells do?
Kill virus-infected cells
What type of H.S. are T cells involved in?
Type IV Delayed cell-mediated H.S.
What else are T-cells involved in?
Acute and Chronic organ rejection
Where does Positive (+) Selection take place?
What happens?
Thymic cortex.
T cells that can bind to self-MHC molecules survive.
Where does Negative (-) Selection take place?
What happens?
Medulla.
T cells that bind too strongly to self-MHC molecules apoptose.
What cytokine enables Helper T to become TH1?
IL-12
What cytokine enables Helper T to become TH2?
IL-4
What happens during naive T cell activation?
- Dendritic cell phagocytoses foreign body.
- Ag is presented on MHC II and recognized by T Helper; Ag is presented on MHC I and recognized by Cytotoxic T
- B7 and CD28 “Co-stimulate”
- T Helper produces cytokines. Cytotoxic T activates and kills virus-infected cells
What cytokine does TH1 secrete?
IFN-y
What is the main job of TH1?
Activate Macrophages
What inhibits TH1?
From TH2:
IL-4
IL-10
What cytokines do TH2 secrete?
IL-4
IL-5
IL-10
IL-13
What are the main jobs of TH2?
Recruit Eosinophils (parasite defense) Promote IgE production by B cells
What inhibits TH2?
From TH1:
IFN-y
