Effects of hCG and beta-hCG on IL-2 and sIL-2R secretion from human peripheral blood mononuclear cells: a dose-response study in vitro.

The effects of human chorionic gonadotropin (hCG) as well as beta-subunit of hCG (B-hCG) in concentrations of: 80,000/25,000; 500; 50; 5 mIU/ml on in vitro release of interleukin-2 (IL-2) and soluble interleukin-2 receptor (sIL-2R) from resting or phytohemagglutinin (PHA) activated human peripheral blood mononuclear cells (PBMC) were studied. Both the interleukins were measured in supernatants of human PBMC by quantitative sandwich enzyme immunoassay method (ELISA). We found that hCG in the dilutions of 80,000 mIU/ml (P < 0.01) and 5 mIU/ml (P < 0.05) diminished IL-2 secretion only from PHA activated PBMC. beta-hCG in concentrations of 5 mIU/ml (P < 0.05), 500 mIU/ml (P < 0.01) and 25,000 mIU/ml (P < 0.05) also diminished IL-2 secretion from PHA activated PBMC, and only in a dilution of 25,000 mIU/ml (P < 0.05) from resting PBMC. Simultaneously, hCG in concentration of 80,000 mIU/ml (P < 0.01) potentiated the release of sIL-2R into supernatants from resting and PHA activated PBMC, but in concentration of 50 mIU/ml (P < 0.05) slightly depressed the secretion of IL-2 from PHA activated PBMC cultures. beta-hCG in dilution of 25,000 mIU/ml (P < 0.001) stimulated the release of sIL-2R from resting or PHA activated PBMC. beta-hCG had also inhibitory effect on sIL-2R secretion from resting (in a dilution of 50 mIU/ml; P < 0.05) and PHA activated (500 mIU/ml; P < 0.01) PBMC. The inhibitory effect of very high concentrations of hCG and beta-hCG on IL-2 secretion together with their stimulatory effect on sIL-2R release from PBMC may be an important event during the human pregnancy and various cancers.