The Carbohydrate Structure of the Hormone hCG, the Autocrine Hyper Glycosylated hCG, and the Extravillous Cytotrophoblast Hyperglycosylated hCG

Objective: Carbohydrate structure has been determined for pregnancy hCG, hydatidiform mole hCG and choriocarcinoma hCG by multiple authors. It has not, however, been discriminated for the three hCG components, the hormone hCG, the autocrine hyperglycosylated hCG or for invasive cell hyperglycosylated hCG. This is determined here. Methods: Three methodologies were used to discriminate the three components of hCG. The B152 immunoassay specifically determines the concentration of hyperglycosylated hCG. Matrigel invasion chambers determine invasiveness of first trimester trophoblast Results: B152 immunoassay binds only hyperglycosylated hCG, and identified all hyperglycosylated hCG in pregnancy hCG, hydatidiform mole hCG and choriocarcinoma hCG preparations. Distribution of triantennary sugar structures same as percent invasion of Matrigel membrane, indicating distribution of invasive extravillous cytotrophoblast component. Recombinant hCG is only hormone hCG, contains 100% Type 1 O-linked oligosaccharides. Identifies Type 1 O-linked oligosaccharide hCG as hormone hCG. Discussion: As determined, first trimester trophoblast cells produced 86.3% hormone hCG (biantennary N-linked and Type 1 O-linked oligosaccharides), 3.5% hyperglycosylated hCG (biantennary N-linked and Type 2 O-linked oligosaccharides) and 13.7% invasive extravillous cytotrophoblast hCG (triantennary N-linked and Type 2 O-linked oligosaccharides). Invasive extravillous cytotrophoblast cells produce 50.4% hormone hCG, 6.0% hyperglycosylated hCG and 42% invasive extravillous cytotrophoblast hCG. Hydatidiform mole cells produce 73.2% hormone hCG, 5.4% hyperglycosylated hCG and 23.4% invasive extravillous cytotrophoblast hCG. Choriocarcinoma cells produce 38.6% hormone hCG, 17.6% hyperglycosylated hCG and 42.8% invasive extravillous cytotrophoblast hCG.