Studies on antilymphocyte antibody in the chicken. I. Effect of rabbit antithymus and antibursa globulin on chicken embryos.

Antithymus globulin (ATG) and antibursa globulin (ABG) prepared in rabbits with thymus and bursa cells were used in experiments on New Hampshire embryos. The assay of potency of ATG and ABG by means of absorption, leucoagglutination, cytotoxicity test and passive haemagglutination showed that ATG and ABG react equally well with both thymus and bursa antigens. Seven-day-old embryos were treated with eleven intrachorioallantoic injections of ATG, ABG and NRG (normal rabbit globulin) from the seventh to seventeenth day of incubation. The incidence of death in embryos receiving ATG and ABG was very high when compared with controls injected with NRG and saline. The ATG affected the cellular make-up of the spleen and bursa, while ABG influenced only the bursa. The cytotoxic-like and development-retarding activity of ATG and ABG were possible only in the presence of guinea-pig complement. The embryonic thymus proved to be resistant to the action of heterologous antilymphocyte antibody.