Antibodies to γ-globulin allotypes were produced in rabbits by immunization with purified rabbit γ-globulin. These antibodies were studied quantitatively by precipitin reaction and shown to be directed towards antigenic determinants occurring on the antibody combining Fragments I and II obtained by papain digestion of rabbit γ-globulin.
Similar allotype specific antibodies could be produced in goats by immunization with one type of rabbit γ-globulin and absorption with another type. One such goat antiserum was found to be capable of precipitating with whole rabbit γ-globulin of the appropriate allotype but not with the papain digest fragments obtained therefrom. Such fragments were, however, shown to inhibit precipitation with whole rabbit γ-globulin, thus indicating their apparent univalence.
When rabbit γ-globulin in the form of a specific precipitate in Freund adjuvant was used for immunization, an antibody specific for human γ-globulin was found in addition to the rabbit allotype specific antibody.