Experimental studies were performed in order to establish autologous adoptive immunotherapy against human solid tumor. When peripheral blood lymphocytes (PBL) from a patient with cholangiocarcinoma (Ch-1) were cultured in the medium supplemented with T cell growth factor for two weeks they proliferated markedly, and more than 100-fold increase in cell number was achieved. These two week-cultured lymphoid cells (CLC2w) were revealed to consist mostly of cytotoxic T cells and, in a portion, of NK cells, from the examination of markers such as SRBC-rosette formation, peroxidase, surface Ig, IgG Fc receptors, C3 receptors, OKT3 antigen, OKT8 antigen, and so on. In in vitro 51Cr-release cytotoxicity assay, fresh PBL from the patient with Ch-1 showed no cytotoxicity against autologous Ch-1 cells which had been maintained by serial transplantations to BALB/c nude mice, whereas CLC2w exerted obvious cytotoxicity against the autologous Ch-1 cells. CLC2w, however, did not lyse PHA-stimulated autologous lymphoblasts. CLC2w also prevented growth of the autologous tumor in nude mice. NK cell activity of CLC2w appeared to be increased as compared with that of fresh PBL from the patient.