Human immunodeficieney virus type 1 hijacks host cyclophilin A for its attachment to target cells

Our laboratory has identified a new facet of human immunodeficiency virus t ype 1 (HIV-1) entry. We demonstrated that the incorporation of host cycloph ilin A (CypA) into nascent viruses is absolutely required for HIV-1 attachm ent to target cells. Although CypA is initially incorporated into the inter ior of the virus, we found that during maturation CypA relocates to the vir al surface. Our work indicates that exposed CypA mediates HIV-1 attachment to target cells via heparans. We believe that this interaction between CypA and heparan represents the initial step in HIV-1 entry.