Decrease in susceptibility to oral tolerance induction and occurrence of oral immunization to ovalbumin in 20-38-week-old mice. The effect of interval between oral exposures and rate of antigen intake in the oral immunization.

Maturation into adulthood, from 8 to 24 weeks of age, significantly influences the induction of oral tolerance in different strains of mice. Animals from strains which are susceptible to the induction of oral tolerance to ovalbumin (OVA) at 8 weeks of age become refractory at 24 weeks of age. Furthermore, in several strains, intermittent exposure to OVA exclusively by gavage resulted in high titres of circulating anti-OVA antibodies. However, the voluntary intake of similar doses of OVA at the same intervals failed to immunize mice of one of the most responsive strains, H-III.