CD9 and infection: Although the mechanism of virus recruitment to the VS in the cis-infection mode remains poorly studied, in trans-infection the recruitment of the following molecules has been observed: tetraspanins (CD81 and CD9) [85], DC-SIGN (dendritic cell-specific intercellular adhesion molecule-3-grabbing non-integrin), ICAM-1, and LFA-1 [87,88].