T-cell receptor Vβ gene usage of human cytotoxic T-cell clones obtained from gastric cancer patients

Nine T-cell clones have been established from tumor-infiltrating lymphocytes (TIL) isolated from ascitic fluid of a gastric cancer patient. Ave of them retained cytotoxicity against autologous tumor cells (AuTu) and were all CD4(+). Each clone had different usage of T-cell receptor (TCR) V beta gene as assessed by Southern blot analysis. Using AuTu and two allogeneic gastric cancer cell lines as targets we selected three clones with unique cytotoxic properties. Two of these clones (Clone I and 2) preferentially lysed AuTu, but showed no or marginal cytotoxicity against allogeneic gastric cancer cells, and one clone (Clone 7) showed appreciable cytotoxicity against AuTu and allogeneic gastric cancer cells. In the detailed analysis of TCRV beta gene usage, Clone 1, 2 and 7 expressed V beta 313.1/D beta 1/J beta 1.5/C beta 1 V beta 3/D beta 2/J beta 2.4/C beta 2 and V beta 9/D beta 1/J beta 1.4/C beta 1, respectively, and the primary structures of the three TCRVb genes did not share any common features, neither in the sizes of their complementarity determining region 3 (CDR3) nor in, their amino acid compositions. Interestingly, PBL of the same patient expressed CDR3 identical to that of Clone 2 and 7, but not that of Clone I. CDR3 identical to that of Clone 2 and 7 were also defected in TIL of other gastric cancer patients. These results show that some AuTu-specific CTL included in Tn a re circulating in peripheral blood, and that the CDR3 identical to that of the CTL is expressed extensively in TIL among different gastric cancer patients. Screening of the expression of the CDR3 in other gastric cancer patients is recommended to develop an immune-therapy of gastric cancer based on antigenic peptide.