CCR5 is a member of the beta chemokine receptors family of integral membrane proteins.In Humans, the CCR5 gene location is on the short (p) arm at position 21 on chromosome 3. Certain populations have inherited the Delta 32 mutation resulting in the Genetic deletion of the CCR5 gene. Homozygous carriers of this mutation are resistant to HIV-1 infection. The CCR5 protein is a seven transmembrane protein which functions as a chemokine receptor in the CC chemokine group. The natural chemokine ligands that bind to this receptor are RANTES, MIP-1α and MIP-1β. CCR5 is predominantly expressed on T cells, macrophages, dendritic cells and microglia. It is likely that CCR5 plays a role in inflammatory responses to infection, though its exact role in normal immune function is unclear.