Effect of carrier preimmunization on neutralizing antibody response of rabbits immunized with beta-human chorionic gonadotropin coupled to tetanus toxoid.

Antisera to the conjugate of beta-human chorionic gonadotropin and tetanus toxoid (beta hCG-TT) generated in rabbits receiving TT carrier preimmunization were characterized and compared with antisera from rabbits receiving the conjugate without preimmunization. Double immunodiffusion and immunoelectrophoresis were used to identify individual antisera components to the conjugate and its substructures. 125IhCG radioimmunoassay indicated similar antibody titers (P = 0.447) regardless of whether the rabbits were preimmunized with TT. However, bioneutralization of native hCG as measured by inhibition of prepubertal rat uterine weight increase was significantly more effective (P = 0.025) with antisera from rabbits which received carrier presensitization. These results demonstrate that carrier preimmunization provides a method for increasing the efficacy of neutralizing antibody produced against haptenic beta hCG.