Effects of Human Chorionic Gonadotropin on Differentiation and Functional Activity of Myeloid-Derived Suppressor Cells

The effect of recombinant human chorionic gonadotropin (hCG) at concentrations of 10 and 100 MU/mL, typical for pregnancy, on differentiation and functional activity of myeloid-derived suppressor cells (MDSCs) was investigated. The subject of the study was isolated cells CD11b(+) that acquired the MDSC phenotype as a result of two-step activation with cytokines GM-CSF and IL-1 beta and lipopolysaccharide (LPS). It was shown that hCG at both concentrations significantly increased the total MDSC pool and at a lower concentration (10 IU/mL) promoted differentiation of the M-MDSC subpopulation. At the same time, 100 MU/mL hCG had no effect on the expression of arginase-1 and indolamine-2,3-dioxygenase (IDO) in MDSCs, but at a concentration of 10 IU/mL there was a tendency to increase IDO expression under the influence of hCG. When the cytokine profile was evaluated by multiplex analysis using Luminex xMAP technology, it was found that hCG did not modulate cytokine production in the CD11b(+) cell culture. Thus, this work demonstrates for the first time that hCG can induce MDSC differentiation.