title: Production of infectious particles from defective human immunodeficiency virus type 1 (HIV-1)-producing cell clones by superinfection with infectious HIV-1.
abstract: A total of 81 cell clones persistently infected with the LAV-1 or HTLV-IIIB strain of human immunodeficiency virus type 1 (HIV-1) was isolated from cells which were obtained by serial passage of some proliferating MT-4 cells after a drastic cytolysis of most cells by HIV-1-infection. These cell clones were classified into 8 types (I to VIII) in terms of the expression of HIV-1 antigens, syncytium formation capacity, and reverse transcriptase activity and infectivity of virus particles in the culture fluid. Type I cell clones were producers of infectious HIV-1 particles, while types II to VIII cell clones did not produce infectious HIV-1 or were producers of uninfectious defective HIV-1 particles. Immunoprecipitation followed by SDS-polyacrylamide gel electrophoresis (PAGE) showed that the gag precursor protein in L-2 cell clone (type IV) was not cleaved to mature gag proteins, while the env precursor protein on L-3 cell clone (type III) was not cleaved to mature env protein. H-7 cell clone (type VIII) did not express any HIV-1 antigen. All these cell clones after the superinfection with infectious HIV-1 synthesized intact gag and env proteins, which were, at least in part, related to the HIV-1 genome persistently present in the cell clones before the superinfection, resulting in production of infectious HIV-1. For example, it was found that L-2 cell clone contained a single copy of the LAV-1 genome per haploid cell and produced doughnut-shaped particles. On the other hand, the cell clone isolated from the L-2 cell clone superinfected with infectious HTLV-IIIB contained the integrated HTLV-IIIB genome in addition to the LAV-1 genome present before the superinfection, and produced intact HIV-1 particles in addition to doughnut-shaped particles from a single cell. These results indicate that complementation and/or genetic recombination events in the superinfected cells may account for the production of infectious intact HIV-1 virions.
authors.affiliation: Section of Serology, Hokkaido University, Sapporo, Japan.
authors.forename: M
authors.initials: M
authors.lastname: Yunoki
authors.forename: K
authors.initials: K
authors.lastname: Maotani-Imai
authors.forename: H
authors.initials: H
authors.lastname: Kusuda
authors.forename: M
authors.initials: M
authors.lastname: Motoyama
authors.forename: S
authors.initials: S
authors.lastname: Miyake
authors.forename: H
authors.initials: H
authors.lastname: Imai
authors.forename: Y S
authors.initials: YS
authors.lastname: Shin
authors.forename: S
authors.initials: S
authors.lastname: Kato
authors.forename: K
authors.initials: K
authors.lastname: Sano
authors.forename: C
authors.initials: C
authors.lastname: Morita
mesh_terms: D000818:Animals; D000911:Antibodies, Monoclonal; D001483:Base Sequence; D015704:CD4 Antigens / Q000096:biosynthesis; D002999:Clone Cells; D004279:DNA, Viral / Q000235:genetics; D003673:Defective Viruses / Q000235:genetics / Q000472:pathogenicity* / Q000648:ultrastructure; D015686:Gene Products, env / Q000096:biosynthesis; D015683:Gene Products, gag / Q000096:biosynthesis; D015497:HIV-1 / Q000235:genetics / Q000472:pathogenicity* / Q000648:ultrastructure; D006801:Humans; D007739:L Cells; D051379:Mice; D008969:Molecular Sequence Data; D011533:Proviruses / Q000235:genetics; D015163:Superinfection
chemical_list: D000911:Antibodies, Monoclonal; D015704:CD4 Antigens; D004279:DNA, Viral; D015686:Gene Products, env; D015683:Gene Products, gag