Modulation of the immune response to transplantation antigens. III. Further studies on the effects of Freund's complete adjuvant on the immune response of mice to allogeneic tumour antigen.

Immunization of mice with allogeneic tumour antigen in Freund's complete adjuvant (FCA) facilitates the growth of subsequent allografts of RI and BP8 tumours in C57/B1 mice. FCA by itself is less effective. In this particular experimental model, antigen given without FCA is not effective. The extent of facilitation depends on the tumour–host combination, on the physical form of the antigen, and on the time interval between pretreatment and tumour allograft. The immunosuppressive effect of FCA appears to be mediated through a direct effect on lymphocytes, largely independent of blocking factors or macrophage effects.