MHC class-I-restricted auto-tumor-specific CD4+CD8- T-cell clones established from autologous mixed lymphocyte-tumor-cell culture (MLTC).

Autologous mixed lymphocyte-tumor cell cultures (MLTC) were initiated with cytokine (IFNγ and TNFα)-treated ex-vivo tumor cells of lung, ovarian, breast and stomach carcinomas. The cytokine-treated tumors expressed class-l but not class-M molecules. Although the proportion of CD8+ lymphocytes increased in the bulk culture of MLTCs, in 5/7 experiments the majority of the established T-cell clones were CD4+. Among the CD8+ clones a high proportion (77%) was cytotoxic, while the proliferative response was more frequent among the CD4+clones (70%). In 4/26 cytotoxic T-lymphocyte (CTL) clones (3/17 CD4+ and I /9 CD8+), derived from a patient with class l+class II− stomach carcinoma, lysis was restricted to the autologous tumor cells. These auto-tumor-specific clones did not lyse the autologous ConA blasts, the 5 allogeneic ex-vivo tumors, the NK-sensitive K562 or the relatively sensitive Daudi cells. The cytotoxicity of these clones was inhibited by pre-incubation of the tumor cells with W6/32 (α-class I) MAb, or by preincubation of the lymphocytes with OKT3 (α-CD3) MAb. The α-CD4 (OKT4) MAb had only a marginal effect on the CD4+clones, while the lytic function of the CD8+ clone was inhibited by the α-CD8 (OKT8) MAb. The 3 CD4+CTL clones also responded with proliferation to the autologous tumor cells. This proliferative response was inhibited by the presence of W6/32 MAb. Our results indicate that the auto-tumor lysis exerted by CD4+ CTL clones was restricted by the class-l antigens, and that the CD4 molecules of the clones were not essential for the lytic interaction. © 1992 Wiley-Liss. Inc.