Eotaxin has been characterized as a chemokine involved in eosinophil activation; however, mRNA for this C-C chemokine has been shown to be constitutively expressed in thymus. Immunohistochemical analysis showed a punctate distribution pattern, with eotaxin expression localized mainly in the medulla and in Hassle’s corpuscles. Moreover, the receptor for eotaxin, CCR-3, was detected on thymocytes, with the highest level of expression being on the CD8 single-positive population. Equilibrium binding analyses on unfractionated thymocytes demonstrated specific I-125-eotaxin binding profiles comparable with CCR-3 transfectants. Eotaxin induced cell migration and mobilization of intracellular calcium in all thymocytes except the immature CD4(-)/CD8(-) population. Eotaxin also induced the secretion of the chemokines interleukin-8, RANTES, and macrophage inflammatory protein-1 beta from thymocyte cultures in vitro. These results suggest that eotaxin-induced thymocyte activation may have important physiological implications for lymphocyte mobilization within and from this lymphoid organ. (C) 1999 by The American Society of Hematology.
Human thymocytes express CCR-3 and are activated by eotaxin
Franz-Bacon, K.; Dairaghi, D. J.; Boehme, S. A.; Sullivan, S. K.; Schall, T. J.; Conlon, P. J.; Taylor, N.; Bacon, K. B.
1999-05-15 / vol 93 / pages 3233-3240
in-vivo; messenger-rna; molecular-cloning; accumulation; allergic inflammation; chemokine receptor; endothelial-cells; eosinophil chemoattractant cytokine; functional expression; receptor ccr3