Adaptive immunity: T cell receptors

Question 1

αβ vs γδ T cell receptors

Answer 1

αβ
-much more common
-recognise MHCs
γδ
-only 1-5% T cells
-directly recognise antigens with broad specificity (no MHC needed!)
-“jack of all trades” -can produce cytokines, present antigens (APC) and be cytotoxic!

Question 2

Thymic selection

Answer 2

+ve selects for TCRs which bind self-MHC
-ve selects for TCRs which bind self-MHC and peptide too strongly

Question 3

How is it ensured that non-thymus proteins are not targeted by TCRs?

Answer 3

autoimmune regulator (AIRE) expresses non-thymus self-proteins so that T cell can recognise them as self