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

Nine T-cell clones have been established from tumor-infiltrating lymphocyte s (TIL) isolated from ascitic fluid of a gastric cancer patient. Ave of the m 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 gastr ic cancer cell lines as targets we selected three clones with unique cytoto xic properties. Two of these clones (Clone I and 2) preferentially lysed Au Tu, but showed no or marginal cytotoxicity against allogeneic gastric cance r cells, and one clone (Clone 7) showed appreciable cytotoxicity against Au Tu and allogeneic gastric cancer cells. In the detailed analysis of TCRV be ta 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 comp lementarity determining region 3 (CDR3) nor in, their amino acid compositio ns. 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 expres sed extensively in TIL among different gastric cancer patients. Screening o f the expression of the CDR3 in other gastric cancer patients is recommende d to develop an immune-therapy of gastric cancer based on antigenic peptide .