Entry to the cell begins through interaction of the trimeric envelope complex (gp160 spike) and bothCD4 and a chemokine receptor (generally eitherCCR5 or CXCR4, but others are known to interact) on the cell surface.gp120 binds to integrinα4β7 activating LFA-1 the central integrin involved in the establishment of virological synapses, which facilitate efficient cell-to-cell spreading of HIV-1. The gp160 spike contains binding domains for both CD4 and chemokine receptors.