Effect of Alpha-Fetoprotein on Differentiation of Myeloid Supressor Cells

The effect of recombinant alpha-fetoprotein (AFP) on human myeloid suppressor cell (MDSC) differentiation was studied in vitro in the presence of cytokines IL-6 (10 ng/mL) and GM-CSF (10 ng/mL). It was found that AFP at concentrations of 50 and 100 IU/mL increased the number of MDSC (CD33⁺ HLA-DR^-/lowCD11b⁺) in culture. Analysis of MDSC subpopulations showed that the increase was due to monocytic M-MDSC (HLA-DR^-/lowCD33⁺CD11b⁺CD14⁺CD66b^-). There was no modulating effect of AFP on granulocytic PMN-MDSC (HLA-DR^-/lowCD33⁺CD11b⁺CD14^-CD66b⁺). The effects of recombinant AFP on MDSC differentiation were thus demonstrated for the first time.