Selective Expression of the Eotaxin Receptor CCR3 by Human T Helper 2 Cells

Abstract

There is growing evidence that T helper cell subsets (T_H1 and T_H2) can be differentially recruited to promote different types of inflammatory reactions. Murine T_H1 but not T_H2 cells are recruited through P- and E-selectin into inflamed tissues, where they induce delayed-type hypersensitivity reactions. The human eotaxin-receptor CCR3, originally described on eosinophils and basophils, was also found to be expressed by T_H2 cells. An antibody to CCR3 was used to isolate T cells from peripheral blood that give rise to T_H2-polarized cell lines and to identify T_H2 cells derived from naı̈ve T cells in vitro. Eotaxin stimulated increases in intracellular calcium and chemotaxis of CCR3⁺ T cells. The attraction of T_H2 cells by eotaxin could represent a key mechanism in allergic reactions, because it promotes the allergen-driven production of interleukin-4 and interleukin-5 necessary to activate basophils and eosinophils.