T LYMPHOCYTE REACTIVITIES TO ALLO- AND ALTERED-SELF ANTIGENS

ABSTRACT The diversity of T lymphocytes that play a role in the response to alloantigens and altered-self antigens is great. In addition to the classical Ly 1, helper T lymphocytes and Ly 2, cytotoxic T lymphocytes, it is now clear that one must consider participation by suppressor T lymphocytes that are separate from the cytotoxic T lymphocytes, and Ly 1,2 T lymphocytes that are involved at the precursor level in the response to K/D alloantigenic stimuli as well as in the response to “altered-self” antigens. It appears that there are two alternative pathways that T lymphocytes can use in their response to foreign antigens: first, a pathway consisting of collaboration between Ly 1, helper T lymphocytes and Ly 2, cytotoxic T lymphocytes and second, a pathway dependent on an Ly 1,2 cell at the precursor level. The factors that may influence the balance between these two pathways as well as consideration of the nature of the antigenic stimuli needed to elicit a secondary response, perhaps dependent on which pathway(s) is used in the primary, are discussed.