Concanavalin A binding of pregnancy-specific beta-1-glycoprotein in normal pregnancy and trophoblastic disease

The binding of pregnancy-specific beta-1-glycoprotein (SP1) to Concanavalin A (Con A) has been studied in serum samples from 34 pregnant women and 13 patients with trophoblastic diseases. In normal pregnancy and in hydatidiform moles, the fraction that did not bind to Con A accounted for 0.5--4.3% of the total SP1 concentration whereas, in 5 out of 6 patients with choriocarcinoma, the fraction was 4.8--30%. The secretion of Con A non-binding SP1 appears to be an inherent characteristic of some malignant trophoblast tissues and may result from its altered glycosylation.