Properties of the progestagen-dependent protein of the human endometrium

Abstract

Antigens A and B, associated with the progestogen-dominated human endometrium, were partly purified and their properties studied. The antigens were recovered in the crude nuclei, the heavy particulate fraction and cytosol of decidua-rich tissue from early pregnancy. The antigens in cytosol were enriched by a combination of Concanavalin A-Sepharose chromatography and polyacrylamide gel electrophoresis. The immunological reactivity of the antigens after partial purification by Concanavalin A-Sepharose chromatography was retained after 30 min exposure to 4-85.degree. C at pH 7.4, or after 2 h to pH 2-12 at 22.degree. C. Trypsin, but not pepsin, RNase, DNase or neuraminidase, completely destroyed immunological reactivity of both antigens. The apparent MW of both antigens determined by filtration on Sephadex G100 was 48,000. The isoelectric point of both antigens was .apprx. 4.9. The antigens were not immunologically related to transferrin, ceruloplasmin, .alpha.-1-antitrypsin, ferritin, uteroglobin, .alpha.-fetoprotein, human chorionic gonadotropin, pregnancy-associated plasma proteins or pregnancy zone protein. The antisera to Antigens A and B did not react with the decidual cytosol of pregnant baboons or of pseudopregnant rats.