Antigens of Human Chorionic Gonadotropin Preparations. I. Fractionation of Pregnancy Urine Human Chorionic Gonadotropin and Isolation of One of Its Specific Antigens1

Publisher Website
Google Scholar
Abstract
Commercial pregnancy HCG preparations do not reliably give pregnancy specific antisera when injected into rabbits. These preparations (400–6500 IU/mg) were reproducibly separated into 5 main fractions by a single stepwise elution from a DEAE-cellulose column. These fractions, as well as solids from pregnancy and nonpregnancy urines, were used to produce antisera in rabbits. These reagents were then used to evaluate pregnancy specificity by immunodiffusion, immunoelectrophoresis and hemagglutination. Some antibodies are readily detected by precipitation but cannot be detected by hemagglutination. Two of the fractions contain at least 2 pregnancy specific antigens and one nonspecific antigen. These fractions (as a proportion of the recovered material) increased when a sample having high biological activity was chromatographed. Immunization with either of these 2 fractions reliably gives specific antisera. The other 3 fractions contain many nonpregnancy contaminants. The elution of biological activity parallels that of one of the pregnancy specific antigens. Rechromatography of either of the 2 “pregnancy specific” fractions produces an immunochemically pure pregnancy specific antigen. Marked quantitative but not qualitative changes in the elution patterns can be caused also by variations in method of sample treatment and size and loading of the column.