Modulation of the immune response to transplantation antigens. IV. Enhanced growth of tumour allografts in mice immunised with papain-solubilised transplantation antigen.
C57/Bl mice have been immunised with papain solubilised CBA transplantation antigen and subsequently challenged with a CBA tumour. Variations in antigen dose, immunisation schedules and routes of injection were compared. Two procedures in particular led to enhanced growth of the tumour allograft: (a) a single injection of antigen seven days before graft, and (b) a two-pulse immunisation spaced over 42 days. Mice given the seven-day course showed impaired cell-mediated cytotoxicity and blocking antibody at the time of challenge which was succeeded by blocking antigen in the circulation after challenge. Mice immunised by the two-pulse course developed heightened cell-mediated cytoxicity, but showed a persisting level of blocking antibody in the serum. Thus, although both immunisation regimes enhanced tumour growth, they did so by different mechanisms.