Tumor Immunity in Hamsters Immunized with Fetal Tissues

Abstract

Abstract Hamster and mouse fetal cells were shown to contain antigen cross-reactive with simian virus 40 (SV40)-induced tumor specific transplantation antigen in stimulating a surface reactive, cytostatic (C) antibody against SV40 tumor target cells in diffusion chambers. The antibody was synthesized when 10-day, but not 14-day, irradiated fetal cells were injected into adult, syngeneic hamsters, and these animals were subsequently found to exhibit immunity to SV40 tumor cell challenge. The spectrum of fetal antigens present in hamster fetus was extended to adenovirus 31-stimulated tumors, and the experimental data afford an explanation of the variability previously noted in the status of immunity to tumor challenge in hamsters immunized with syngeneic fetal tissues. The failure of unirradiated fetal cells to induce transplantation immunity was correlated in this work with the development of embryomas or teratomas at the site of immunization. Males responded to fetal immunization better than did female animals although multiparous, pregnant hamsters developed C antibody during pregnancy, and lost it post-partum. The role of fetal antigenic expression in cancer and cancer immunology is considered in relation to these findings.