Question

1. How does a double positive T cell become a mature T cell? Include the selection process. 2. What is the effector function of CD8+ T cells? How do they cooperate with CD4+ T cell effector functions? 3. What specifically drives the formation of each subset of Th effector cells? How do these Th effector cells respond once activated (i.e. what are their effector mechanisms?)

Answer 1

(1) double positive Pre- T cells undergo to selection processes in the thymus. Positive and negative selection.

In case of positive selection double positive Pre T cells interact with self MHC molecule expressed on epithelial cells in the Thymic cortex.this interaction result in the survival and differentiation of double positive cells. Double positive cells that do not make this critical interaction and are not selected die by apoptosis.

Negative selection is the process in which T cells whose TCR bind strongly to self peptide antigen in association with self MHC molecules are deleted. this removes. T Cells expressing TCR bind strongly to self autoreactive against self antigens and develop self tolerance.

C-CDY E-TER DP. Tallerede positive selection Cell sunive if Recepty of T cells interact with selfmhe Death by apoptosis if receptor of cells don not interact with one molecules Megative selection y death of cells Ac & Death of calls of Recepty have high Affinity for selfmnc Cell selected of Receptor have neeak Affinity of or sell mise more maturation , ok coa maturation / . O copt

C-CDY E-TER DP. Tallerede positive selection Cell sunive if Recepty of T cells interact with selfmhe Death by apoptosis if receptor of cells don not interact with one molecules Megative selection y death of cells Ac & Death of calls of Recepty have high Affinity for selfmnc Cell selected of Receptor have neeak Affinity of or sell mise more maturation , ok coa maturation / . O copt