The Monoclonal Antibody CHO-131 Identifies a Subset of Cutaneous Lymphocyte-Associated Antigen T Cells Enriched in P-Selectin-Binding Cells

Abstract

T cells use the vascular adhesion molecules E- and P-selectin to enter inflamed skin. Previous studies have indicated the possibility for diversity in the synthesis of E- and P-selectin glycan ligands by activated T cells due to their different requirements for the O-glycan branching enzyme core 2 β1,6-N-acetylglucosaminyltransferase I and its independent regulation. It is known that T cell staining by the mAb HECA-452 (referred to as cutaneous lymphocyte-associated Ag (CLA) T cells) correlates with E-selectin binding, yet whether these cells uniformly bind P-selectin is less clear. The mAb CHO-131 and P-selectin binding require a glycan moiety consisting of a sialylated and fucosylated oligosaccharide properly positioned on a core-2 O-glycan. Interestingly, CHO-131 stains a subset of CLA+ T cells. A direct comparison of the selectin binding capacity of CHO-131+ and CHO-131− CLA+ T cells revealed a significantly greater P-selectin, but not E-selectin, binding activity by the former subset. Based on the expression of homing and central and effector memory cell markers, CHO-131+ and CHO-131− CLA+ T cells have an overlapping skin-tropic and memory phenotype. CHO-131+ T cells were considerably enriched in psoriatic skin, yet, unlike the peripheral blood of healthy individuals, HECA-452 and CHO-131 stained a similar proportion of T cells in the cutaneous lesions, indicating an accumulation advantage by CHO-131+ T cells. We conclude that the CHO-131+CLA+ T cell subset is enriched in P-selectin binding cells. These findings should provide new insights into the regulation and function of skin homing T cells.