Background: Pregnancy-specific β1-glycoproteins are capable of regulating innate and adaptive immunity, exerting predominantly suppressive effects. In this regard, they are of interest in terms of their pharmacological potential for the treatment of autoimmune diseases and post-transplant complications. The effect of these proteins on the main pro-inflammatory subpopulation of T lymphocytes, IL-17-producing helper T cells (Th17), has not been comprehensively studied. Therefore, the effects of the native pregnancy-specific β1-glycoprotein on the proliferation, Th17 polarization and cytokine profile of human CD4+ cells were assessed.
Results: Native human pregnancy-specific β1-glycoprotein (PSG) at а concentration of 100 μg/mL was shown to decrease the frequency of Th17 (RORγτ+) in CD4+ cell culture and to suppress the proliferation of these cells (RORγτ+Ki-67+), along with the proliferation of other cells (Ki-67+) (n = 11). A PSG concentration of 10 μg/mL showed similar effect, decreasing the frequency of Ki-67+ and RORγτ+Ki67+ cells. Using Luminex xMAP technology, it was shown that PSG decreased IL-4, IL-5, IL-8, IL-12, IL-13, IL-17, MIP-1β, IL-10, IFN-γ, TNF-α, G-CSF, and GM-CSF concentrations in Th17-polarized CD4+ cell cultures but did not affect IL-2, IL-7, and MCP-1 output.
Conclusions: In the experimental model used, PSG had а mainly suppressive effect on the Th17 polarization and cytokine profile of Th17-polarized CD4+ cell cultures. As Th17 activity and a pro-inflammatory cytokine background are unfavorable during pregnancy, the observed PSG effects may play a fetoprotective role in vivo.
Keywords: Cytokine profile; Helper T cells; Interleukin-17; Pregnancy; Pregnancy-specific β1-glycoprotein; RORγτ transcription factor.