Limiting dilution analysis of alloreactive T-cell status and distribution during allograft rejection

We have developed limiting dilution analysis techniques that discriminate between precursor T cells and T cells that have responded to prior contact with alloantigens. We used these techniques to monitor the behavior of functional T-lymphocyte subsets in sponge matrix allograft recipients. Thus, we were able to measure at the graft site and/or in the peripheral blood (1) all donor-reactive cytotoxic T lymphocytes, (2) the subset of donor-reactive cytotoxic T lymphocytes that has responded to graft alloantigens in vivo, (3) all donor-reactive helper T lymphocytes, and (4) the subset of donor-reactive helper T lymphocytes that has responded to graft alloantigens in vivo. In this communication, we describe some aspects of the in vivo T-cell response to allograft implantation that were revealed by this study.