T cells, specifically cytotoxic T cells (T8L), typically recognize foreign peptides presented by self-MHC molecules. However, they can also recognize foreign MHC molecules during graft rejection. This occurs because T cells can be activated by foreign MHC molecules that present antigens, leading to the recognition of the graft as non-self. The interaction between T cells and foreign MHC is critical in transplant immunology, as it explains how the immune system can identify and attack transplanted tissues that express non-self MHC, resulting in graft rejection. Understanding this mechanism is essential for improving transplant outcomes and developing strategies to mitigate rejection.
