Frequency in human peripheral blood of T cells which respond to self, modified self and alloantigens.

The frequency of occurrence in human peripheral blood of T cells able to proliferate in the autologous mixed lymphocyte reaction (AMLR), and in response to trinitrophenyl (TNP)-modified self (AMLR-TNP) and alloantigens, was measured by limiting dilution analysis. AMLR responder cells were found to have a precursor frequency of from 1/7500 to 1/44,000 peripheral blood T cells. T cells able to respond to hapten modified self were about twice as common and those responding to alloantigen had a 10-fold greater frequency. Responses of T cells remaining after Budr plus light treatment of AMLR or AMLR-TNP-activated T cells indicate that these T cells are in overlapping populations. Their relation to alloreactive T cells is not clear at present. Although responses to alloantigens remained, and indeed were slightly enhanced, after Budr plus light treatment of self-reactive T cells, the experimental design does not rule out the possibility that some self-reactive T cells are also alloreactive.