Recombinant human macrophage inflammatory protein-1α (rhMIP-1α) and rhMIP-1β were potent chemoattractants of human T lymphocytes. These rhMIP-1 cytokines attracted only T cells activated by monoclonal antibody to CD3 and did not attract unstimulated lymphocytes. Phenotypic analysis revealed that CD4⁺ T cells were capable of migrating in response to rhMIP-1β, whereas rhMIP-1α induced chemotaxis of predominantly CD8⁺ T lymphocytes. Activated naive and memory T cells also migrated in response to rhMIP-1 cytokines. Furthermore, these cytokines enhanced the ability of T cells to bind to an endothelial cell monolayer. These results suggest that rhMIP-1 cytokines preferentially recruit specific T cell subsets during the evolution of the immune response.