Summary
Mice exposed soon after birth to crystalline bovine serum albumin acquire an immune tolerance for this antigen, which lasts for several weeks.
This tolerance is demonstrated by the lack of anaphylactic response to a challenge following suitable sensitizing injections. The sensitizing procedure was one that produced a high incidence of anaphylaxis in normal (neonatally not exposed) litter mates.
Tolerance is also demonstrated by an almost complete lack of circulating antibodies as measured by the Farr technique (ammonium sulfate precipitation of labeled antigen in immune serum).
The acquired tolerance diminishes with time and is succeeded by a state of hypersensitivity. The mechanism for the establishment of tolerance and immunity in mice may therefore coexist during the first 2 weeks of life.
The degree and duration of the tolerant state is related to the amount of antigen given during the early postnatal period.
An interpretation of these results has been presented based on the assumption that antigen is retained at intracellular sites.