Jamaican Fruit-eating Bat (Artibeus jamaicensis) and Common Vampire Bat (Desmodus rotundus) CCL5 (C–C motif chemokine ligand 5, also known as RANTES – Regulated upon Activation, Normal T cell Expressed and Secreted) is a proinflammatory chemokine involved in immune cell recruitment and antiviral immune responses. CCL5 belongs to the CC chemokine family, which includes related chemokines such as CCL3 (MIP-1α), CCL4 (MIP-1β), and CCL2 (MCP-1) that regulate leukocyte trafficking during immune activation. In both Jamaican Fruit-eating bats and Common Vampire bats, the CCL5 protein is identical at the amino acid level, indicating strong evolutionary conservation and suggesting similar biological functions in these two bat species. CCL5 is produced primarily by activated T lymphocytes, macrophages, dendritic cells, platelets, and epithelial cells in response to viral infection, inflammatory stimuli, or tissue injury. It exerts its biological effects mainly through binding to the chemokine receptors CCR1, CCR3, and CCR5, which activates intracellular signaling pathways that promote chemotaxis and activation of T cells, monocytes, macrophages, eosinophils, and natural killer (NK) cells at sites of infection or inflammation. In bats, chemokines such as CCL5 likely contribute to antiviral defense and coordination of innate and adaptive immunity, particularly during infections with viruses that many bat species naturally harbor. Because Jamaican Fruit-eating bats and Common Vampire bats are recognized reservoirs for multiple emerging viruses, characterization of CCL5 helps support research into bat immune regulation, chemokine-mediated leukocyte recruitment, and host–pathogen interactions that enable bats to tolerate viral infections while limiting excessive inflammatory damage.