Characterization of a promonocyte clone chronically infected with HIV and inducible by 13-phorbol-12-myristate acetate.

Abstract

The present study has investigated the effect of PMA, an inducer of monocyte differentiation, on HIV expression in a chronically infected promonocyte clone. After acute HIV infection of U937 cells, clones that constitutively expressed varying levels of HIV were isolated by limiting dilution. One clone (U1) produced low levels of HIV but was found to increase its production 20-fold after PMA induction, as detected by reverse transcriptase or A capture. Further characterization of U1 indicated that PMA could induce cellular differentiation and maturation in the clone similar to that in uninfected U937 cells. In addition, functional studies revealed that superoxide anion production from the U1 clone was not different from that of uninfected U937 cells. Electron microscopic studies of U1 indicated that PMA induced endocytotic vesicles containing many HIV particles. These studies provide a model at the clonal level to 1) examine latency or chronicity of HIV infection in monocytes and 2) delineate the signals required for conversion to high level viral expression.

Recruitment of human cyclin T1 to nuclear bodies through direct interaction with the PML protein

“…To prove that PML is also recruited to the viral LTR upon transcriptional activation of virus‐infected cells, we applied the ChIP method to U1 cells, a cell line chronically infected with HIV‐1 and bearing two copies of the HIV provirus that are transcriptionally silent in the absence of stimulation (Folks et al ., 1988). After treatment of these cells with 1 × 10 −7 M 12‐ o ‐tetradecanoylphorbol‐13‐acetate (TPA) for 5 h, a treatment that results in transcriptional activation and viral replication (Demarchi et al ., 1993), followed by ChIP with an anti‐PML antibody, we observed a 2.3‐fold enrichment for the DNA segment encompassing the LTR, but not for the control B13 region (the competitive PCR results are shown in Figure 7G and H, and are summarized in I).…”

Extracellular vesicle isolation methods identify distinct HIV‐1 particles released from chronically infected T‐cells

“…The HIV‐1 lymphadenopathy‐associated virus (LAV) infected T‐cell lines J1.1 LAV (ARP, cat#1340) (Folks et al., 1987 ; Perez et al., 1991 ), ACH‐2 (LAV) (ARP, cat#349) (Folks et al., 1989 ), and the promonocytic U1 (LAV) (Folks et al., 1988 ) (ARP, cat#165), cell lines were obtained through the NIH AIDS Reagent Program. The MOLT‐4 T‐cell line was obtained from ATCC (crl‐1582™).…”

Infection of CD4+ Primary T Cells and Cell Lines, Generation of Chronically Infected Cell Lines, and Induction of HIV Expression

“…The HIV provirus or proviruses present in these cells frequently contain mutations, as in the case of U1 cells, which carry proviruses defective in the Tat-TAR axis (Cannon et al, 1994). Chronically infected RT-negative and envelope-negative cell lines (such as 8E5 and U33.3, respectively) have also been described (Folks et al, 1986b;1988;Poli et al, 1990). However, persistently infected cell lines producing infectious HIV, such as the ACH-2 cell line (Folks et al, 1986a;Stanley et al, 1991), have also been obtained.…”

“…This phenomenon indicates that a fraction of cells have not been depleted by the virus. These "survivor" cells frequently show a profound down-modulation of the CD4 molecule from the plasma membrane as a consequence of HIV infection, and contain a low number (1 to 2) of integrated proviral DNA copies (Folks et al, 1986a(Folks et al, , 1986b(Folks et al, , 1988. Because these survivor cells maintain an endless proliferative capacity, they are considered chronically infected.…”