The effects of low-dose irradiation on the active enhancement of tumor allografts

Active immunologic enhancement is believed to be a phenomenon in which a specific antibody, actively produced by the host, interferes with the host's ability to mount a normal cell-mediated immune reaction against the antigen. The authors' previous experiments have shown that CBA mice given i.p. injections of A/J spleen can no longer reject A/J-derived sarcoma I (SaI) tumor allografts. Mice bearing enhanced tumors develop nylon-wool-nonadherent, I-J super(+) suppressor T cells (Ts) capable of transferring tumor allograft enhancement into naive CBA recipients. Sublethal irradiation (300 rads) of the CBA recipients prior to suppressor cell transfer augments of the activity of the suppressor cells. This led the authors to examine the effects of low-dose irradiation on the generation of active enhancement in six-to-twelve-week-old female mice.