RAPID COMMUNICATION Human Immunodeficiency Virus (HIV)-Resistant CD4 UT-7 Megakaryocytic Human Cell Line Becomes Highly HIV-1 and HIV-2 Susceptible Upon CXCR4 Transfection: Induction of Cell Differentiation by HIV-1 Infection

Recent findings have shown that the expression of the seven dered UT-7 cells readily infectable by different T-lymphotropic syncytium-inducing HIV-1 and HIV-2 isolates. Interesttrans-membrane G-protein–coupled CXCR4 (the receptor for the stromal cell-derived factor [SDF]-1 chemokine) is necesingly, HIV-1 infection of CXCR4 expressing UT-7 cells (named UT-7/fus) induces the formation of polynucleated cells sary for the entry of T-lymphotropic human immunodeficiency virus (HIV) strains, acting as a coreceptor of the CD4 through a process highly reminiscent of megakaryocytic differentiation and maturation. On the contrary, no morphomolecule. In the human system, the role of CXCR4 in HIV infection has been determined through env-mediated cell logic changes were observed in HIV-2–infected UT-7/fus cells. These findings further strengthen the role of CXCR4 fusion assays and confirmed by blocking viral entry in CD4/ CXCR4 cells by SDF-1 pretreatment. We observed that the as a molecule necessary for the replication of T-lymphotropic HIV-1 and HIV-2 isolates and provide a useful model to study human megakaryoblastic CD4 UT-7 cell line fails to express CXCR4 RNA and is fully resistant to HIV entry. Transfection the functional role of CD4 coreceptors in HIV infection. q 1997 by The American Society of Hematology. of an expression vector containing the CXCR4 c-DNA ren-