THE ALLOGENEIC EFFECT IN INBRED MICE : IV. REGULATORY INFLUENCES OF GRAFT-VS.-HOST REACTIONS ON HOST T LYMPHOCYTE FUNCTIONS

The studies presented herein were designed to directly evaluate the effects of a transient GVH reaction on T lymphocyte functions. To this end, we have shown that generation of carrier-specific helper cell function can be significantly influenced by the allogeneic effect. Thus, carrier-primed helper cells derived from CAF₁ donor mice were generally much more active in specifically cooperating with syngeneic 2,4-dinitrophenyl (DNP)-primed B cells in adoptive recipients when parental A strain lymphocytes had been administered at some time during the priming regimen. This was true when allogeneic cells were administered concomitantly with the initial priming dose of carrier protein as well as when the GVH was induced in animals that had been exposed to antigen several days previously. This indicates that the allogeneic enhancing effects can be manifested on either primed or unprimed T cell populations. The ultimate effect of the GVH reaction on the development of helper T cell activity was found to be related to the number of allogeneic cells employed and the duration of the resultant GVH reaction in the carrier-primed host animal. Hence, allogeneic stimulation of slightly greater magnitude and/or longer duration resulted in marked suppression rather than enhancement of helper cell function in such donor mice. These findings may have general relevance to problems in autoimmune diseases and tumor immunity.