簡要描述：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 a