Rôle des différentes formes d'ADN viral dans la réplication et la persistance du Virus de l'Immunodéficience Humaine de type 1

PARIS-BIUSJ-Thèses (751052125) / SudocPARIS-BIUSJ-Physique recherche (751052113) / SudocSudocFranceF

Evidence for Gene Expression by Unintegrated Human Immunodeficiency Virus Type 1 DNA Species

The integrated form of human immunodeficiency virus type 1 (HIV-1) DNA is classically considered to be the sole template for viral gene expression. However, several studies have suggested that unintegrated viral DNA species could also support transcription. To determine the contribution of the different species of HIV-1 DNA to viral expression, we first monitored intracellular levels of various HIV-1 DNA and RNA species in a single-round infection assay. We observed that, in comparison to the precocity of HIV-1 DNA synthesis, viral expression was delayed, suggesting that only the HIV-1 DNA species that persist for a sufficient period of time would be transcribed efficiently. We next evaluated the transcriptional activity of the circular forms of HIV-1 DNA bearing two long terminal repeats, since these episomes were reported to exhibit an intrinsic molecular stability. Our results support the notion that these circular species of HIV-1 DNA are naturally transcribed during HIV-1 infection, thereby participating in virus replication

Analysis of Early Human Immunodeficiency Virus Type 1 DNA Synthesis by Use of a New Sensitive Assay for Quantifying Integrated Provirus

A novel Alu-long terminal repeat (LTR)-based real-time nested-PCR assay was developed to quantify integrated human immunodeficiency virus type 1 (HIV-1) DNA in infected cells with both accuracy and high sensitivity (six proviruses within 50,000 cell equivalents). Parallel assays for total HIV-1 DNA and two-LTR HIV-1 DNA circles allowed the synthesis and fate of the different HIV-1 DNA species to be monitored upon a single round of viral replication

Lack of endogenous TRIM5alpha-mediated restriction in rhesus macaque dendritic cells.

International audienceRhesus macaques are resistant to infection by HIV-1 as a result of an innate cellular restriction mechanism attributable to the expression of rhTRIM5alpha, a member of the large tripartite motif (TRIM) protein family. TRIM5alpha-mediated restriction, which occurs before reverse transcription through targeting of the HIV-1 capsid, has been identified in a number of macaque primary cells and cell lines and is thought to occur in all macaque cell types. We report, however, that rhesus macaque dendritic cells (DCs) lack TRIM5alpha-mediated restriction and are equally permissive to HIV-1 infection as human DCs. Evidence suggests that, although TRIM5alpha RNA levels are normal in these cells, the protein may be dysfunctional. We propose that abrogation of TRIM5alpha-mediated restriction in DCs, although still operative in cells that replicate HIV-1 (macrophages, T lymphocytes), illustrates the need for innate mechanisms to not inhibit adaptive immune responses to ensure an optimal fight against pathogens

Nonpathogenesis of Simian Immunodeficiency Virus Infection Is Associated with Reduced Inflammation and Recruitment of Plasmacytoid Dendritic Cells to Lymph Nodes, Not to Lack of an Interferon Type I Response, during the Acute Phase▿

Divergent Toll-like receptor 7 (TLR7) and TLR9 signaling has been proposed to distinguish pathogenic from nonpathogenic simian immunodeficiency virus infection in primate models. We demonstrate here that increased expression of type I interferon in pathogenic rhesus macaques compared to nonpathogenic African green monkeys was associated with the recruitment of plasmacytoid dendritic cells in the lymph nodes and the presence of an inflammatory environment early after infection, instead of a difference in the TLR7/9 response

Viral contamination in biologic manufacture and implications for emerging therapies

Recombinant protein therapeutics, vaccines, and plasma products have a long record of safety. However, the use of cell culture to produce recombinant proteins is still susceptible to contamination with viruses. These contaminations cost millions of dollars to recover from, can lead to patients not receiving therapies, and are very rare, which makes learning from past events difficult. A consortium of biotech companies, together with the Massachusetts Institute of Technology, has convened to collect data on these events. This industry-wide study provides insights into the most common viral contaminants, the source of those contaminants, the cell lines affected, corrective actions, as well as the impact of such events. These results have implications for the safe and effective production of not just current products, but also emerging cell and gene therapies which have shown much therapeutic promise

Impairment of Human Immunodeficiency Virus Type-1 Integrase SUMOylation Correlates with an Early Replication Defect*

HIV-1 integrase (IN) orchestrates the integration of the reverse transcribed viral cDNA into the host cell genome and participates also in other steps of HIV-1 replication. Cellular and viral factors assist IN in performing its multiple functions, and post-translational modifications contribute to modulate its activities. Here, we show that HIV-1 IN is modified by SUMO proteins and that phylogenetically conserved SUMOylation consensus motifs represent major SUMO acceptor sites. Viruses harboring SUMOylation site IN mutants displayed a replication defect that was mapped during the early stages of infection, before integration but after reverse transcription. Because SUMOylation-defective IN mutants retained WT catalytic activity, we hypothesize that SUMOylation might regulate the affinity of IN for co-factors, contributing to efficient HIV-1 replication