Abstract
Summary: Immunologic tolerance was induced in adult CBA mice by a single injection of the supernatant from ultracentrifuged bovine γ-globulin (BGG). Mice so treated and later challenged with BGG-Bentonite did not produce detectable antibody as measured by the disappearance rate of I125 BGG or by the microhemagglutination method. The sediment from pooled ultracentrifuged BGG induced antibody formation rather than tolerance. Tolerance could be produced by as little as 0.19 mg of supernatant BGG. Such tolerance could be partially overcome by 19 mg, but not by 1.9 mg of BGG-Bentonite. Partial tolerance was induced by 0.019 mg of supernatant BGG. Tolerance could not be produced by supernatant BGG when it was accompanied by an intravenous dose of 100 µg of bacterial endotoxin.