RANTES

RANTES, a chemokine also known as CCL5, is a small cytokine of the CC chemokine family that functions primarily as a chemoattractant for immune cells. It is produced by various cell types, including activated T cells, monocytes, endothelial cells, fibroblasts, and platelets, and can be released from platelet alpha granules upon activation.

It guides the migration of T lymphocytes, eosinophils, basophils, and natural killer cells to sites of inflammation, and it can amplify immune responses by promoting leukocyte recruitment and activation. RANTES exerts its effects by binding to several chemokine receptors, notably CCR1, CCR3, and CCR5, with receptor usage varying by cell type and local environment. The protein is typically secreted as a small, basic protein and is part of the early chemokine response to infection or tissue injury.

Clinical significance: In HIV infection, the receptor CCR5 is a co-receptor for R5-tropic strains; by occupying CCR5, RANTES can inhibit viral entry, a property explored in research and in CCR5-targeted therapies, such as CCR5 antagonists. RANTES has also been implicated in allergic inflammation and asthma due to its eosinophil-attracting activity, and elevated expression has been observed in some inflammatory and infectious diseases. The precise role of RANTES can be context-dependent, contributing to host defense or to pathology depending on the tissue and disease state.

History: The molecule was first described as a T cell-derived chemotactic factor and was named Regulated upon Activation, Normal T cell Expressed and Secreted, later designated CCL5.