Kinetics of antibody response in animals injected with processed beta-HCG conjugated to tetanus toxoid (Pr-β-HCG-TT)

Abstract

Processed beta-subunit of HCG conjugated covalently to tetanus toxoid (Pr-β-HCG-TT) was found to be immunogenic in a number of species of animals tested. Single or multiple injections of the conjugate were required depending on the adjuvant used. The conjugate gives rise to the concomitant formation of antibodies against both HCG and tetanus toxoid. In rhesus monkeys, the antibodies appeared after a lag period of a few weeks, and increased progressively to attain plateau levels anywhere between 9 and 20 weeks. The duration of antibody response after primary immunization in most monkeys was beyond one year. The response was reversible and antibody titers declined to insignificantly low levels in course of time. A single repeat injection was adequate to evoke a powerful secondary immune response. The conjugate elicits the formation of antibodies with fairly high affinity constants for binding with HCG. Ka values ranged from 10⁹ to 10¹⁰ L/mole.