Antigens and receptors involved in bone marrow transplantation

The author's studies show that the antigens recognized by T cells in the allograft reaction are complex and that this antigenic complexity is matched by the diversity of the T-cell receptors, with receptors for the individual antigenic determinants being clonally distributed. The finding that a minute alteration of the H-2 molecule, probably a single amino acid substitution, can lead to an elicitation of a response that is sometimes as powerful as that against multiple differences presented by the entire H-2 complex, is depressive. It shows that the obstacles to bone marrow transplantation might be even more formidable than we had all thought so far.