Affinity to lectin, biological and immunological characteristics of human chorionic gonadotropins from pregnant women and trophoblastic tumour patients.

To compare the affinity to lectin of human chorionic gonadotropins (hCG) from pregnant women and trophoblastic tumour patients, a small amount of urine was fractionated by a lentil lectin (LcH) affinity chromatography. The LcH-bound fractions were eluted with 2% mannoside solution, and each fraction was assayed for hCG activities by radioimmunoassay. In pregnant women, more than 90% of hCG immunoactivity in urine was bound to the LcH column and eluted from it, whereas 8 to 26% and 37 to 51% of the activity were not adsorbed to the affinity column and were recovered in the LcH-unbound fraction in the patients with hydatidiform mole and choriocarcinoma, respectively. These results suggest that LcH affinity chromatography of urinary hCG contributes to differential diagnosis between pregnancy and trophoblastic tumours. To characterize the properties of hCG from the urine of choriocarcinoma patients, with or without the LcH affinity, hCG activities in both LcH-unbound and LcH-bound fractions were measured by in vivo and in vitro bioassays and each of the activities was compared with the activities measured by radioimmunoassay. The results showed that the LcH-unbound fraction contained hCG molecules defecting to induce the biological activity of hCG in vivo.