Formulation of a potential antipregnancy vaccine based on the beta-subunit of human chorionic gonadotropin (beta-hCG). I. Alternative macromolecular carriers.

The antibody response obtained after vaccinating rabbits with the beta-subunit of human chorionic gonadotropin (beta-hCG) linked to several protein and polysaccharide carriers was measured. In all but one preparation, carbodiimide was used to couple the beta-hCG to the carrier. Tetanus toxoid (TT) and cholera vaccine proved the most effective carriers among those examined. TT from different manufacturers proved to be greatly different in free amino group content and differed in ability to participate in the coupling reaction. Reasonably good replication of the coupling reaction was obtained with different production lots from the same manufacturer. Inferior antigenic response was obtained with the products of coupling beta-hCG to H. pertussis, influenza vaccine, polylysine, pneumococcus polysaccharide, or E. coli polysaccharide. The findings indicate TT and cholera vaccine to be especially effective in enhancing the antigenicity of a weakly antigenic peptide but point to significant differences in the TT from different manufacturers.