Early and enhanced antioxin responses elicited with complexes of tetanus toxoid and specific mouse and human antibodies.

Primary tetanus antitoxin responses were early and enhanced in mice when tetanus toxoid was administered in complex with specific isologous antitoxin or specific mouse gamma-globulin. Antoxin responses were enhanced when fluid tetanus toxoid was complexed in vitro in antigen-to-antibody ratios of equivalence or antigen excess; responses to complexed toxoid in antibody excess were comparatively repressed. Primarly responses were greatly inhibited in mice immunized with the same amount ot toxoid complexed in vitro in antigen-to-antibody ratios of equivalence or antigen excess; responses to complexed toxoid in antibody excess were comparatively repressed. Primary responses were greatly inhibited in mice immunized with the same amount of toxoid complexed at equivalence or in antibody excell with specific human gamma-globulin. Although primary responses. Separate injections of antigen and antibody at different sites produced an excelldnt antitoxin responses. Separate injections of antigen and antibody at different sites produced an excellent in vivo primed state for early and high responses. Antibody production after stimulation with complexed toxoid was also enhanced in mice irradiated with 400 rad, a dose that ordinarily completely suppresses primary responses with fluid toxoid alone. These data provide evidence for the efficacy of antigen-antibody complexes in early and active immunization.