Chemokine receptor expressions and responsiveness of cord blood T cells

Chemokines and their receptors play a critical role in the selective attrac tion of various subsets of leukocytes. We examined the chemokine receptor e xpressions and responsiveness of cord blood (CB) T cells. Flow-cytometric a nalysis revealed that peripheral blood (PB)T cells expressed CCR-1, CCR-2, CCR-5, CCR-6, CXC chemokine receptor-3 (CXCR-3), and CXCR-4, while CB T cel ls expressed only CXCR-4 on their surface. Chemotactic migratory response o f CB T cells to macrophage-inflammatory protein (MIP)-1 alpha, monocyte che moattractant protein-1, RANTES, MIP-3 alpha, monokine induced by IFN-gamma, and IFN-gamma -inducible protein-10 was significantly impaired compared wi th those of PB T cells. In contrast, the ability of CB T cells to migrate t o MIP-3 beta, 6Ckine, and stromal cell-derived factor-la was greater than t hat of PB T cells, and these events were correlated with the expression lev els of CCR-7 and CXCR-4, respectively. Engagement of CD3 and CD28 specifica lly up-regulated CXCR3 expression and chemotaxis to monokine induced by IFN -gamma and IFN-gamma -inducible protein-10, whereas this stimulation down-r egulated CCR-7 expression and chemotaxis to MIP-3 beta and 6Ckine in PB T c ells, but not in CB T cells, These results suggest that PB T cells and CB T cells exhibit distinct chemokine responsiveness via different chemokine re ceptor repertoire.