CCR5 and HIV infectious disease: However, there is evidence that CCR5 monomers are likely to mediate HIV infection based on experiments showing that HIV replication was blocked in human peripheral blood mononuclear cells (PBMCs) ex vivo, and in vivo in mouse models, by CCR5 dimerisation: this dimerisation, similar to that induced by RANTES (a natural chemokine with anti-HIV activity) was induced by anti-CCR5 mAbs that did not interfere with HIV gp120 binding or chemokine binding, and that did not trigger CCR5 signalling or internalisation [241].