A LYMPHOCYTE-SPECIFIC CC-CHEMOKINE, SECONDARY LYMPHOID-TISSUE CHEMOKINE (SLC), IS A HIGHLY EFFICIENT CHEMOATTRACTANT FOR B-CELLS AND ACTIVATED T-CELLS

Secondary lymphoid tissue chemokine (SLC) is a CC chemokine expressed mainly in lymph nodes, appendix and spleen, and specifically chemotact ic for lymphocytes (Nagira et at., J. Biol. Chem. 1997. 272: 19518-195 24). Here, we carried out transendothelial migration assays to determi ne the classes and subsets of lymphocytes migrating toward SLC. SLC at tracted freshly isolated B cells with high efficiency and T cells mode stly. Thus, SLC is the first CC chemokine with a strong chemotactic ac tivity on fresh B cells. Among T cell types and subsets, SLC broadly a ttracted CD4(+) and CD8(+) cells, CD45RO(-) (naive) and CD45RO(+) (mem ory) cells, and CD26(high) (activated) and CD26(low/-)(resting) cells. SLC also attracted both L-selectin(+) and L-selectin(-) subpopulation s of various T cell subsets and B cells. Furthermore, mitogenic stimul ation strongly enhanced migratory responses of T cells and B cells tow ard SLC. By in situ hybridization, SLC mRNA was detected in the cortic al parafollicular regions (the T cell areas) of a lymph node and an ap pendix. Collectively, SLC may be a basic chemokine supporting homeosta tic migration of a broad spectrum of lymphocytes into the secondary ly mphoid tissues. SLC may also be involved in immune responses by induci ng highly efficient migration of T and B cells following antigenic sti mulation.