Subsets of oncofetal antigen-induced T-cells: ability to mediate antitumor immune response.

The present study was performed to identify the subsets of oncofetal antigen-induced T-cells that mediate antitumor immune response in mice. In this study, performed on a weakly immunogenic, metastatic tumor, fetal antigen-sensitized spleen cells significantly inhibited the growth and metastases of tumors in Winn neutralization assay. Mixing of spleen cells from tumor-bearing inbred C57BL/6J mice with fetal antigen-sensitized spleen cells completely abolished the tumor inhibitory effect of fetal antigen-sensitized spleen cells. Further characterization of fetal antigen-sensitized spleen cells showed that they were Thy-1+. These findings reveal that tumor-associated fetal antigens on fetal cells can produce a tumor inhibitory T-cell immune response against the growth and metastases of a weakly immunogenic, metastatic tumor. The subset of oncofetal antigen-induced T-cells that mediates antitumor immune response was identified as Lyt-1+ and Lyt-2-. Adoptive transfer of fetal antigen-sensitized spleen cells to mice with preestablished metastases significantly inhibited the lung metastases in these mice, thus making this approach more relevant to a clinical situation in cancer patients.