HIV-1 replication is controlled at the level of T cell activation and proviral integration.

Abstract

During progression of the Acquired Immune Deficiency Syndrome (AIDS), the human immunodeficiency virus type 1 (HIV‐1) is harbored in CD4+ T cells, which act as the primary reservoir for the virus. In vitro, HIV‐1 requires activated T cells for a productive infection; however, in vivo, the number of circulating T cells in the activated state that are potential targets for HIV‐1 infection is low. We have investigated the ability of HIV‐1 to infect resting T cells, and the consequences of such an infection. T cell activation was not required for HIV‐1 infection; however, viral DNA was unable to integrate in resting T cells and was maintained extrachromosomally. Subsequent T cell activation allowed integration of extrachromosomal forms and led to a productive viral life cycle. Extrachromosomal forms of viral DNA were found to persist for several weeks after infection of resting T cells and, following T cell activation, these forms maintained their ability to integrate and act as a template for infectious virus. Several lines of evidence, including temporal analysis of HIV‐1 replication and analysis of an HIV‐1 integrase deletion mutant, indicated that extra‐chromosomal HIV‐1 DNA genomes were transcriptionally active. These results are compatible with a model whereby HIV‐1 can persist in a non‐productive extra‐chromosomal state in resting T cells until subsequent antigen‐induced or mitogen‐induced T cell activation, virus integration and release. Thus agents that induce T cell activation may control the rate of HIV‐1 replication and spread during AIDS progression.

Characterization of Restrictions to Human Immunodeficiency Virus Type 1 Infection of Monocytes

“…However, although exogenous stimulation of dNTP levels enhanced reverse transcription and generation of full-length transcripts, this did not overcome the block to infection. These and other studies (22,26) support the notion that a block subsequent to reverse transcription prevents productive infection of quiescent lymphocytes. Upon infection of monocytes, reverse transcription was highly inefficient when analyzed up to 66 h postinfection and was not improved by normalization of dNTP levels (Fig.…”

Upregulation of cyclin T1/CDK9 complexes during T cell activation

“…From the data in Table 1, HIV replication fold over non-stimulated PBLs at 72 h Syncytia formation in non-stimulated and stimulated PBLs as measured by the infected centers assay (see Materials and methods). a Syncytia/10 4 cells (Stevenson et al, 1990;Zack et al, 1990). In activated T cells, the viral DNA is integrated and HIV replication depends on viral accessory proteins and host factors (Cullen, 1998;Finzi and Silliciano, 1998).…”

Efficient lentiviral transduction of Herpesvirus saimiri immortalized T cells as a model for gene therapy in primary immunodeficiencies

“…MLV-based vectors, on the other hand, were quite inefficient and never transduced more than 1% of the cells. We demonstrated that eGFP detection in HVS-T cell lines transduced with HRSIN-CSGW represents vector transduction (and not pseudotransduction 16 or expression from nonintegrated vectors 17,18 ) since the percentage of eGFP þ cells remained stable for at least 48 days as shown in Figure 2. This also supports that gene silencing 19 is not occurring in lentiviral-transduced HVS-T cells.…”

“…This is important since transgene detection in target cells may be due to pseudotransduction 16 (especially at high MOIs) or expression from nonintegrated vectors. 17,18 Additionally, the expression of the transgene by transduced cells can be blocked by gene silencing. 19 The expression of eGFP protein was determined on days 7, 28 and 48 after a single round of cell transduction on day one.…”