RANTES is a CC chemokine that mediates chemo-taxis and activation of T cells, eosinophils, basophils, monocytes, dendritic cells and even neurons. Many cell types express RANTES in response to inflammatory mediators and RANTES is released from intracellular storage granules of platelets and eosinophils upon activation. RANTES is a high-affinity ligand for the chemokine receptors CCR1, CCR3, CCR5, and the cytomegalovirus receptor LS28. RANTES is able to inhibit R5 (macrophage-tropic) HIV-l entry via the CCR5 receptor and RANTES expression by T cells may be important in the pathogenesis of AIDS.