Immunological properties of dinitrophenyl derivatives of beta-subunit of the human chorionic gonadotropin

Abstract

Four different derivatives with varying proportions of dinitrophenyl (DNP) groups tagged covalently to β-subunit of HCG (DNP₍₁₎-β-HCG, DNP_(3.3)-β-HCG, DNP₍₆₎-β-HCG and DNP₍₁₀₎-β-HCG) have been prepared. Their immunogenicity as well as the reactivity of antibodies formed in mice, rabbit and rhesus monkey have been studied. The derivatives give rise to the formation of antibodies in all species tested which react with HCG and in some species with DNP moieties. The anti-DNP response increases with derivatives bearing more than 3-4 DNP groups per molecule of β-HCG. On the other hand the anti-HCG response diminishes with derivatives bearing higher than 3-4 DNP groups per β-HCG molecule. The antibody response in monkeys is of long duration (>14 months). The association constants for binding with HCG are of the order of 4×10⁹ to 6×10¹⁰ L/mole. the affinity of the antibodies tends to increase with time.