FUNCTIONAL AND MOLECULAR CHARACTERIZATION OF GRAFT-INFILTRATING T-LYMPHOCYTES PROPAGATED FROM DIFFERENT BIOPSIES DERIVED FROM ONE HEART-TRANSPLANT PATIENT

Alloreactive T lymphocytes play an important role in graft rejection. In the present study, we have analyzed the cytolytic capacity against donor cells of graft infiltrating T lymphocyte cell lines, which were propagated from various endomyocardial biopsies taken at different tim e points after transplantation, including during a rejection crisis. A lso, T cell clones were generated from the rejection biopsy and evalua ted for their cytolytic capacity and nucleotide composition of the TCR alpha and beta chains. The results of these studies revealed a strong cytolytic activity against donor cells by T cells derived from the re jection biopsy, whereas from the other biopsies, no cytolytic T cell c lones could be established. The T cells that were responsible for this activity, as detected by T cell cloning and TCR gene analysis, could not been identified in earlier biopsies, indicating that these cytolyt ic cells were recently recruited toward the endomyocardium.