CCL3 (C-C motif chemokine ligand 3) represents a small inducible cytokine. The encoded protein, also known as macrophage inflammatory protein 1 alpha, plays a role in inflammatory responses through binding to the receptors CCR1, CCR4 and CCR5. Polymorphisms at this locus (CCL3) may be associated with both resistance and susceptibility to infection by human immunodeficiency virus type 1.