Antibody production in avian embryos and young chicks.

Abstract

SUMMARY: The inoculation of killed Salmonella pullorum into the developing avian embryo on or after the 17th day of incubation or of live Sal. pullorum into young chicks evoked no immediate antibody response. Approximately 20–40 days after hatching, however, agglutinins and non-agglutinating antibodies were sometimes detected in the sera of these chicks. Maximum antibody production did not occur until the chicks were approximately 100 days old. The intravenous inoculation of killed Sal. pullorum into developing embryos on or before the 15th day of incubation stimulated the production of practically no demonstrable antibody by the chicks during approximately the first 80 or 100 days after hatching. These chicks, however, showed a marked decrease in capacity to produce demonstrable antibodies in their sera after subsequent oral infection with Sal. pullorum. These experimental results are discussed in relation to various theories of antibody production. It is suggested that they are evidence in support of Burnet’s adaptive enzyme theory. The results are explained on the hypothesis that the introduction of antigenic material into the embryo under suitable experimental conditions enables the host cells to become adapted to the antigen, resulting in a diminished antibody response by the host, during post-embryonic life, to a subsequent challenge with similar antigenic material.