Envelope glycoproteins from human immunodeficiency virus types 1 and 2 and simian immunodeficiency virus can use human CCR5 as a coreceptor for viral entry and make direct CD4-dependent interactions with this chemokine receptor - Hill,C.M.; Deng,H.; Unutmaz,D.; Kewalramani,V.N.; Bastiani,L.; Gorny,M.K. (J Virol, 1997)