Final answer:
The process where donor dendritic cells cause transplant rejection by presenting alloantigens to recipient T cells is called 'transplant rejection.' It is predominantly mediated by cytotoxic T cells targeting MHC molecules perceived as non-self.
Step-by-step explanation:
The correct term for the process where donor dendritic cells from an organ transplant present alloantigens to recipient T cells, which then destroy the transplanted organ, is known as transplant rejection. During this process, the recipient's immune system recognizes the donor tissue as foreign, due in large part to the expression of different major histocompatibility complex (MHC) molecules, specifically MHC I and MHC II (or human leukocyte antigens - HLAs). These foreign MHC molecules are identified as non-self by the recipient's immune system, particularly dendritic cells, which then process and present them to helper and cytotoxic T cells, initiating an immune response. Activated cytotoxic T cells essentially target and kill the grafted tissue cells. This cellular attack results in the destruction of the transplanted organ or tissue, leading to the failure of the graft.