The cytotoxic activity and T cell receptor (TCR) V beta repertoire in tumor-infiltrating lymphocytes (TIL) of three primary adrenal cell carcinomas were analyzed. Fresh, non-cultured TIL from two of the three tumors showed low but significant lysis of the autologous tumor, and for one of the patients this activity was strongly enhanced upon culture in interleukin-2. An allogeneic adrenal cell carcinoma line and the K562 or Daudi targets included as controls were not killed. Phenotypic analysis of freshly isolated TIL demonstrated that the cells from the two patients that demonstrated cytolytic capacity mainly consisted of CD45RO+ T cells. In vitro cultured TIL lines from these patients demonstrated a high percentage of CD8+ cells expressing either the V beta 6 gene or the V beta 8 gene product, as measured with a panel of mAb specific for TCR V alpha and V beta gene products. Analysis of the TCR V beta gene mRNA expression in freshly isolated non-cultured TIL, using a polymerase-chain-reaction-assisted cDNA-amplification assay, confirmed the strong expression of the genes coding for the TCR V beta 6 or the V beta 8. This assay also demonstrated a more restricted TCR V beta gene usage in the TIL as compared to peripheral blood lymphocytes from the same patient.