CD195, also known as CCR5, is a 45 kD G protein-coupled seven transmembrane CC-chemokine receptor. It binds to MIP-1alpha, MIP-1beta, and RANTES and is expressed on a subset of T cells and monocytes. CD195 mediates an intracellular signal thought to induce cell differentiation and proliferation. CCR5 has also been shown to act as a co-receptor for R5 HIV-1 cell entry; modification of CCR5 by sulfation contributes to the efficiency of HIV-1 entry. Recent studies have shown CCR5 to play a role in a variety of other human diseases, ranging from infectious and inflammatory diseases to cancer.