CD31+ T cells represent a functionally distinct vascular T cell phenotype

In contrast to CD3(+)/CD31(-) cells, CD3(+)/CD31(+) cells aid in endothelial repair and revascularization. There are limited data regarding the functional differences between circulating CD3(+)/CD31(+) and CD3+/CD31(-) cells that may contribute to their divergent cardiovascular effects. The aim of the present study was to characterize functional differences between CD3(+)/CD31(+) and CD3(+)/CD31(-) cells. To address this aim, migratory capacity, proangiogenic cytokine release and apoptotic susceptibility of CD3(+)/CD31(+) and CD3(+)/ CD31(-) cells were determined. Human CD3(+)/CD31(+) and CD3(+)/CD31(-)cells from peripheral blood were isolated using magnetic-activated cell sorting. CD3(+)/CD31(+) cells demonstrated significantly higher (similar to 60%) migratory capacity to the chemokines SDF-1 alpha (655 +/- 99 vs. 273 +/- 54 AU) and VEGF (618 +/- 99 vs. 259 +/- 57 AU) vs. CD3(+)/CD31(-) cells. Release of angiogenic cytokines G-CSF, interleukin-8 and matrix metallopeptidase-9 were all similar to 100% higher (P<0.05) in CD3(+)/CD31(+) than CD3(+)/CD31(-) cells. CD3(+)/CD31(+) cells exhibited significantly higher intracellular concentrations of active caspase-3 (2.61 +/- 0.60 vs. 0.34 +/- 0.09 ng/ mL) and cytochrome-c (21.8 +/- 1.4 vs. 13.7 +/- 1.0 ng/mL). In summary, CD3(+)/CD31(+) cells have greater migratory and angiogenic cytokine release capacity, but are more susceptible to apoptosis compared with CD3(+)/CD31(-) cells. Enhanced migratory capacity and angiogenic cytokine release may contribute to the vasculogenic properties of this unique T cell subpopulation. (C) 2009 Elsevier Inc. All rights reserved.