processing-bronchoalveolar-lavage-fluid-matched-blood-for-alveolar

Processing of Bronchoalveolar Lavage Fluid and Matched Blood for Alveolar Macrophage and CD4<sup>+</sup> T-cell Immunophenotyping and HIV Reservoir Assessment

Bronchoscopy is a medical procedure whereby normal saline is injected into the lungs via a bronchoscope and then suction is applied, removing ...

Centre de Recherche du Centre Hospitalier de l'Université de Montréal

Université de Montréal

The HIV-1 infection is characterized by profound CD4(+) T cell destruction and a marked Th17 dysfunction at the mucosal level. Viral suppressive antiretroviral therapy restores Th1 but not Th17 cells. Although several key HIV dependency factors (HDF) were identified in the past years via genome-wide siRNA screens in cell lines, molecular determinants of HIV permissiveness in primary Th17 cells remain to be elucidated.

Identification of novel HIV-1 dependency factors in primary CCR4(+)CCR6(+)Th17 cells via a genome-wide transcriptional approach.

With the increasing number of therapeutic strategies tested in humans to reduce the size of the latent reservoir, the development of a robust, precise and clinical trial scalable assay that measures the frequency of infected cells carrying inducible replication-competent HIV is urgently needed. The size of the pool of cells carrying replication-competent HIV is largely overestimated by DNA assays, as a result of a large proportion of defective viruses, and underestimated by co-culture outgrowth assays. New culture methods that measure the inducible HIV reservoir have been developed during the past few years. In these induction assays, CD4 T cells from virally suppressed individuals are activated and HIV RNA is measured in cell extracts or cell supernatants. In this review, we summarize the principle and outcomes of these assays and discuss the potential of these methods in the evaluation of HIV eradication strategies.

Inducible HIV RNA transcription assays to measure HIV persistence: pros and cons of a compromise.

HIV persists in latently infected CD4 T cells during antiretroviral therapy (ART). Immune checkpoint molecules, including PD-1, are preferentially expressed at the surface of persistently infected cells. However, whether PD-1 plays a functional role in HIV latency and reservoir persistence remains unknown. Using CD4 T cells from HIV-infected individuals, we show that the engagement of PD-1 inhibits viral production at the transcriptional level and abrogates T-cell receptor (TCR)-induced HIV reactivation in latently infected cells. Conversely, PD-1 blockade with the monoclonal antibody pembrolizumab enhances HIV production in combination with the latency reversing agent bryostatin without increasing T cell activation. Our results suggest that the administration of immune checkpoint blockers to HIV-infected individuals on ART may facilitate latency disruption.

Article	Year
Identification of novel HIV-1 dependency factors in primary CCR4(+)CCR6(+)Th17 cells via a genome-wide transcriptional approach. Retrovirology\| PubMed ID: 26654242	2015
Inducible HIV RNA transcription assays to measure HIV persistence: pros and cons of a compromise. Retrovirology\| PubMed ID: 29343255	2018
PD-1 blockade potentiates HIV latency reversal ex vivo in CD4 T cells from ART-suppressed individuals. Nature communications\| PubMed ID: 30778080	2019

Nicolas Chomont

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