Immunological properties of the β-subunit of human chorionic gonadotropin

The β-subunit of human chorionic gonadotropin (hCG-β) has been modified to a varying degree by the cleavage of the disulfide bonds by reduction with dithioerythritol followed by S-carboxamidomethylation. The resulting derivatives of hCG-β show a preferential loss in their immunological cross-reactivity with human luteinizing hormone (hLH). The immunological specificity of the partially reduced and S-alkylated derivatives can be further enhanced by conjugation with tetanous toxoid using glutaraldehyde. Neither conjugation of hCG-β with the toxoid nor its treatment with anti-hLH immunoadsorbent affects its cross-reactivity with hLH.