title: Envelope gene sequences encoding variable regions 3 and 4 are involved in macrophage tropism of feline immunodeficiency virus.
abstract: The envelope is of cardinal importance for the entry of feline immunodeficiency virus (FIV) into its host cells, which consist of cells of the immune system including macrophages. To characterize the envelope glycoprotein determinants involved in macrophage tropism, chimeric infectious molecular clones were constructed containing envelope gene sequences from isolates that had been propagated in peripheral blood mononuclear cells (PBMC). The progeny virus was examined for growth in PBMC and bone marrow-derived macrophages and viruses with different replication kinetics in macrophages were selected. Envelope-chimeric viruses revealed that nucleotide sequences encoding variable regions 3 and 4 of the surface glycoprotein, SU, are involved in macrophage tropism of FIV. To assess the biological importance of this finding, the phenotypes of envelope proteins of viruses derived from bone marrow, brain, lymph node and PBMC of an experimentally FIV-infected, healthy cat were examined. Since selection during propagation had to be avoided, provirus envelope gene sequences were amplified directly and cloned into an infectious molecular clone of FIV strain Petaluma. The viruses obtained were examined for their replication properties. Of 15 clones tested, 13 clones replicated both in PBMC and macrophages, two (brain-derived clones) replicated in PBMC only and none replicated in Crandell feline kidney cells or astrocytes. These results indicate that dual tropism for PBMC and macrophages is a common feature of FIV variants present in vivo.
authors.affiliation: Virology Unit, Department of Infectious Diseases and Immunology, Faculty of Veterinary Medicine, Utrecht University, Yalelaan 1, 3584 CL Utrecht, The Netherlands1.
authors.forename: Thomas W
authors.initials: TW
authors.lastname: Vahlenkamp
authors.affiliation: Department of Human Retrovirology, Academic Medical Centre, Amsterdam, The Netherlands2.
authors.forename: Anthony
authors.initials: A
authors.lastname: De Ronde
authors.affiliation: Virology Unit, Department of Infectious Diseases and Immunology, Faculty of Veterinary Medicine, Utrecht University, Yalelaan 1, 3584 CL Utrecht, The Netherlands1.
authors.forename: Nancy N M P
authors.initials: NNMP
authors.lastname: Schuurman
authors.affiliation: Virology Unit, Department of Infectious Diseases and Immunology, Faculty of Veterinary Medicine, Utrecht University, Yalelaan 1, 3584 CL Utrecht, The Netherlands1.
authors.forename: Arno L W
authors.initials: ALW
authors.lastname: van Vliet
authors.affiliation: Virology Unit, Department of Infectious Diseases and Immunology, Faculty of Veterinary Medicine, Utrecht University, Yalelaan 1, 3584 CL Utrecht, The Netherlands1.
authors.forename: Judith
authors.initials: J
authors.lastname: van Drunen
authors.affiliation: Virology Unit, Department of Infectious Diseases and Immunology, Faculty of Veterinary Medicine, Utrecht University, Yalelaan 1, 3584 CL Utrecht, The Netherlands1.
authors.forename: Marian C
authors.initials: MC
authors.lastname: Horzinek
authors.affiliation: Virology Unit, Department of Infectious Diseases and Immunology, Faculty of Veterinary Medicine, Utrecht University, Yalelaan 1, 3584 CL Utrecht, The Netherlands1.
authors.forename: Herman F
authors.initials: HF
authors.lastname: Egberink
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D002415:Cats; D002460:Cell Line; D003001:Cloning, Molecular; D005814:Genes, Viral; D016089:Immunodeficiency Virus, Feline / Q000145:classification / Q000235:genetics* / Q000502:physiology*; D016180:Lentivirus Infections / Q000473:pathology / Q000821:virology; D008264:Macrophages / Q000821:virology*; D008969:Molecular Sequence Data; D017422:Sequence Analysis, DNA; D018523:Tropism; D014759:Viral Envelope Proteins / Q000235:genetics*
chemical_list: D014759:Viral Envelope Proteins