We have studied the binding of
human chorionic gonadotropin (hCG) in sera and urine of normal pregnant women and patients with trophoblastic diseases to the
lectin from peanut (Arachis hypogaea, PNA). As the basic experiments, purified standard hCG and its alpha and beta subunits were examined for binding to a PNA-
Sepharose column. Both standard hCG and
hCG-beta adsorbed to the PNA-
Sepharose only when they were treated with
neuraminidase, whereas
hCG-alpha was still not adsorbed even
after treatment with
neuraminidase. The major proportions of hCG in sera and urine from normal pregnancy and
hydatidiform mole were not adsorbed to the PNA-
Sepharose column. On the other hand, the proportions of PNA binding fraction in sera and urine from
choriocarcinoma were significantly elevated in 4 of 6 cases. The PNA binding fraction was significantly higher in serum than in urine of each individual. The PNA binding fractions were extracted and purified from urine of 2 patients with
choriocarcinoma, and were quantitatively found to be
asialo-hCG. These results suggest that PNA-
Sepharose affinity chromatography is an effective tool to use in detecting incompletely sialylated hCG and
hCG-beta and may be a useful index for the clinical diagnosis of
choriocarcinoma.