BIOLOGICAL AND IMMUNOLOGICAL CHARACTERIZATION OF ANTIGONADOTROPHIC PROFILES

ABSTRACT During the past few years a series of papers (Robyn et al. 1968; Robyn & Diczfalusy 1968a,b,c; Robyn et al. 1969; Petrusz et al. (1970) were published from this laboratory on the problems of statistically valid bioassays of gonadotrophin neutralizing potencies of antisera. These bioassays were based on the principle of »simple additivity« (or rather, subtractivity) of Hormone (H) and Antiserum (AS). Experiments conducted at several levels of neutralization of H by AS, ranging from 20 to 90 %, supported the validity of the principle of »simple additivity«. The human chorionic gonadotrophin (HCG), the luteinizing hormone (LH) and the follicle stimulating hormone (FSH) neutralizing potencies of rabbit anti-HCG sera, anti-human hypophysial gonadotrophin (anti-HHG) sera and anti-human menopausal gonadotrophin (anti-HMG) sera were estimated comparatively. The establishment of such antigonadotrophic profiles of antisera has several advantages. It makes it possible to improve the biological specificity of antisera by absorption procedures carried out on a strictly quantitative basis by selecting an appropriate amount of a gonadotrophin preparation with the adequate LH:FSH ratio. Also, it makes possible to improve the biological specificity of gonadotrophin preparations by absorption procedures carried out on a quantitative basis by selecting the appropriate excess of an antiserum with the adequate anti-LH:anti-FSH ratio. Finally the characterization of the antigonadotrophic profile of antisera together with that of the gonadotrophic profile of antigens provides improved tools for the study of the very complex relationships between the biological activities and the antigenic properties of gonadotrophic molecules. It is hoped, therefore, that the use of these methods will be of assistance in improving the specificity of current immunoassays for gonadotrophins.