The influence of salicyl-azo-sulfapyridine on the immune response to antigenic tumour cells inoculated into the coecal lumen of C3H mice.

Pretreatment of C3H mice with salicyl-azo-sulfapyridine (SASP) was found to increase the susceptibility of the intestine to malignant ascites cells inoculated into the coecal lumen. The response to intestinal immunization was radically changed by prior treatment of mice with SASP. In non-treated animals protection against a subsequent graft followed the intracoecal inoculation of ascites tumour cells. By prior treatment of the mice with SASP the protective immune response was suppressed and some of the treated animals showed enhanced tumour growth of the challenging graft. The immunological enhancement induced in SASP-treated animals was transferable by spleen cells to untreated mice. In sera from SASP-treated and intestinally immunized animals were found factors which in a competitive manner interfered with the binding of antibodies to antigenic sites on the tumour cell membrane. It is proposed that treatment with SASP modifies the intestinal immunity by suppressing antibody production and increasing production of antigen-specific factors lacking some of the immunoglobulin determinants.