title: CD4-independent, CCR5-dependent simian immunodeficiency virus infection and chemotaxis of human cells.
abstract: Most simian immunodeficiency virus (SIV), human immunodeficiency virus type 2 (HIV-2), and HIV-1 infection of host peripheral blood mononuclear cells (PBMCs) is CD4 dependent. In some cases, X4 HIV-1 chemotaxis is CD4 independent, and cross-species transmission might be facilitated by CD4-independent entry, which has been demonstrated for some SIV strains in CD4(-) non-T cells. As expected for CCR5-dependent virus, SIV required CD4 on rhesus and pigtail macaque PBMCs for infection and chemotaxis. However, SIV induced the chemotaxis of human PBMCs in a CD4-independent manner. Furthermore, in contrast to the results of studies using transfected human cell lines, SIV did not require CD4 binding to productively infect primary human PBMCs. CD4-independent lymphocyte and macrophage infection may facilitate cross-species transmission, while reacquisition of CD4 dependence may confer a selective advantage for the virus within new host species.
authors.affiliation: Department of Molecular Microbiology and Immunology, School of Public Health, Johns Hopkins University, Baltimore, Maryland 21205, USA.
authors.forename: S
authors.initials: S
authors.lastname: Iyengar
authors.forename: D H
authors.initials: DH
authors.lastname: Schwartz
authors.forename: J E
authors.initials: JE
authors.lastname: Clements
authors.forename: J E
authors.initials: JE
authors.lastname: Hildreth
mesh_terms: D000818:Animals; D015704:CD4 Antigens / Q000502:physiology; D002478:Cells, Cultured; D002634:Chemotaxis, Leukocyte; D006801:Humans; D007963:Leukocytes, Mononuclear / Q000276:immunology / Q000821:virology*; D008253:Macaca mulatta; D008254:Macaca nemestrina; D019713:Receptors, CCR5 / Q000378:metabolism / Q000502:physiology*; D015302:Simian Immunodeficiency Virus / Q000235:genetics / Q000276:immunology / Q000502:physiology*
chemical_list: D015704:CD4 Antigens; D019713:Receptors, CCR5