O-Glycosylation of NnTreg Lymphocytes Recognized by theAmaranthus leucocarpusLectin

Abstract

O-glycosidically-linked glycans have been involved in development, maturation, homing, and immune regulation in T cells. Previous reports indicate thatAmaranthus leucocarpuslectin(ALL), specific for glycans containing galactose-N-acetylgalactosamine and N-acetylgalactosamine, recognizes human naïve CD27+CD25+CD4+T cells. Our aim was to evaluate the phenotype of CD4+T cells recognized byALLin peripheral blood mononuclear cells obtained from healthy volunteers. CD4+T cells were isolated by negative selection using magnetic beads-labeled monoclonal antibodies; the expression of T regulatory cell phenotypic markers was assessed onALL-recognized cells. In addition, IL-4, IL-10, IFN-γ, and TGF-βintracellular production inALL+cells was also evaluated. The analyses of phenotypic markers and intracellular cytokines were performed through flow cytometry.ALL-recognized CD4+T cells were mainly CD45RA+, CCR7+cells. Although52±10% CD25+Foxp3+cells were positive toALL, only34±4% ofALL+cells corresponded to CD25+Foxp3−cells. Intracellular cytokines in freshly obtainedALL+CD4+T cells exhibited 8% of IL-4, 15% of IL-10, 2% of IFN-γ, and 15% of TGF-β, whereasALL−CD4+T cells depicted 1% of IL-4, 2% of IL-10,<1% of IFN-γ, and 6% of TGF-β. Our results show that galactose-N-acetylgalactosamine and N-galactosamine-bearing CD4+T cells expressed phenotypic markers of NnTreg cells.