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.

Persistent infection of MT-4 cells by human immunodeficiency virus type 1 becomes increasingly likely with in vitro serial passage of wild-type but not nef mutant virus

“…The M10 clonal cell line (Yunoki et al, 1991), which was derived from the MT-4 cell line (Miyoshi et aL, 1982) was cultured in complete medium (RPMI-1640 medium supplemented with 10 % fetal bovine serum) at 37 °C in a CO 2 incubator. The inocula for wild-type and nef HIV-1 were the conditioned media from SW480 cells transfected, as described previously (Adachi et al, 1987), with a pNL432 plasmid containing full-length HIV-I DNA (Adachi et al, 1986) and a pNL-Xh plasmid , respectively.…”

“…We have previously reported an abnormal HIV-1 life cycle in persistently HIV-l-infected cells obtained from the human T cell lymphotropic virus type I-transformed MT-4 cell line or from its clonal derivative, M10, after infection with HIV-1 (Ikuta et al, 1988;Yunoki et al, 1991). In this system, infected cells were drastically reduced in number by the killing of single cells rather than by the induction of syncytia, a mechanism similar to that observed in normal peripheral blood mononuclear cells.…”

Cells surviving infection by human immunodeficiency virus type 1: vif or vpu mutants produce non-infectious or markedly less cytopathic viruses

“…We have reported an abnormal HIV-1 life cycle in persistently HIV-1-infected cells obtained after infection of human T cell lymphotrophic virus type I (HTLV-I)-transformed MT-4 cells or its clonal derivative M 10 with HIV-1 (Ikuta et al, 1988;Yunoki et al, 1991). The infected MT-4 and M10 cells were drastically reduced in number by single-cell killing rather than by the induction of syncytia.…”

Positive and Negative Aspects of the Human Immunodeficiency Virus Protease: Development of Inhibitors versus Its Role in AIDS Pathogenesis

“…A subclone (named L-2), which produces noninfectious HIV particles (124,153,373) and carries a provirus with a 1-base insertion in the pol PR (10), thus is a producer of the doughnut-shaped, RT-negative, and noninfectious HIV particles (similar to those seen in Fig. 3A).…”