Genetic differences in immune exclusion and partial tolerance to ingested antigens.

The effect of feeding ovalbumin was studied in CBA, C3H, SWR/J and A inbred strains of mice. In non-immune animals differences were observed in their abilities to absorb intact antigen and eliminate it from their circulation. Following oral immunization, C3H mice were able to absorb significantly less ovalbumin than controls, however no evidence for immune exclusion was found in the other strains. Oral tolerance could be induced in all strains tested but in CBA and SWR/J mice oral immunization had to be continual, via the drinking rather than a single daily gastric intubation. The results suggest that genetic differences exist in the handling of antigen by the gut. If similar differences exist in man they may underly differences in susceptibility to food allergy.