Question

In the following bone marrow chimera, donor MHCa, recipient MHC a x b which of the following statements is correct?

a. Mature T cells will in the periphery will bind APC with MHC a or MHCb.
b. Mature T cell will bind only APC MHCa
c. Only T cells that recognize APC MHC b will be leaving the thymus.
d. Cells that recognize APC with NHC a or MHC b will die from apoptosis
e. T cells that recognize both MHC a and MHC b become anergic.

Answer 1

In a bone marrow chimera with donor MHC type a and recipient MHC a x b, the correct statement is that mature T cells in the periphery will bind to APCs with either MHC a or MHC b, thanks to negative selection during T cell development favoring cells that recognize both MHC haplotypes without inducing autoimmunity.

Step-by-step explanation:

In the context of bone marrow chimeras where the donor has Major Histocompatibility Complex (MHC) type a and the recipient has MHC type a x b, the correct statement regarding which mature T cells in the periphery will bind to Antigen-Presenting Cells (APCs) is: Mature T cells will in the periphery will bind APC with MHC a or MHC b. This is because during the process of T cell development in the thymus, negative selection ensures that T cells that strongly recognize self-antigens presented on MHC molecules of the body undergo apoptosis to prevent autoimmune responses.

The resulting mature T cells can then recognize and bind to foreign antigens presented by either donor MHC molecules (MHCa) or recipient MHC molecules (MHC a or MHC b). Therefore, these cells are selected for their ability to recognize both MHC haplotypes, without inducing an auto-immune response, which might occur if they only recognized one type of MHC.