CD4 and infection: While the formation of the virological synapse depends on the interaction between the viral gp120 envelope glycoprotein and the CD4 receptor, the infectious synapse formed during trans-infection does not rely upon CD4/gp120 interaction since Rodriguez-Plata et al. showed that the number of cell-to-cell conjugates formed between DCs and CD4+ T cells was not increased in the presence of HIV-1 (85).