Human Immunodeficiency Virus (HIV) and Simian Immunodeficiency Virus (SIV) require coreceptors to enter and infect target cells. They are dependent upon an interaction between the viral envelope glycoprotein with T cell antigen T4 (CD4) and a G protein coupled receptor (GPCR). HIV1 infection relies upon interaction with a chemokine receptor, usually chemokine (C-C) receptor 5 (CCR5). During progression of the infection, the virus tends to rely upon chemokine (C-X-C) receptor 4 (CXCR4). SIV also utilizes CCR5 in the early stages of infection, but during progression it tends to rely on two orphan GPCR's named chemokine (C-X-C) receptor 6 (Bonzo) and G protein coupled receptor 15 (BOB/GRP15). Bonzo mRNA expression has been localized to lymphoid tissues and activated peripheral blood lymphocytes.Synonyms: BONZO, CDw186, CXC-R6, CXCR-6, G-protein coupled receptor STRL33, G-protein coupled receptor bonzo, STRL33, TYMSTR