Exploring histone loading on HIV DNA reveals a dynamic nucleosome positioning between unintegrated and integrated viral genome.

The aim of the present study was to understand the biology of unintegrated HIV-1 DNA and reveal the mechanisms involved in its transcriptional silencing. We found that histones are loaded on HIV-1 DNA after its nuclear import and before its integration in the host genome. Nucleosome positioning analysis along the unintegrated and integrated viral genomes revealed major differences in nucleosome density and position.

Corrigendum: CD32a is a marker of a CD4 T-cell HIV reservoir harbouring replication-competent proviruses.

This corrects the article DOI: 10.1038/nature21710.

CD32a is a marker of a CD4 T-cell HIV reservoir harbouring replication-competent proviruses.

The persistence of the HIV reservoir in infected individuals is a major obstacle to the development of a cure for HIV. Here, using an in vitro model of HIV-infected quiescent CD4 T cells, we reveal a gene expression signature of 103 upregulated genes that are specific for latently infected cells, including genes for 16 transmembrane proteins. In vitro screening for surface expression in HIV-infected quiescent CD4 T cells shows that the low-affinity receptor for the immunoglobulin G Fc fragment, CD32a, is the most highly induced, with no detectable expression in bystander cells.

Elevated Basal Pre-infection CXCL10 in Plasma and in the Small Intestine after Infection Are Associated with More Rapid HIV/SIV Disease Onset.

Elevated blood CXCL10/IP-10 levels during primary HIV-1 infection (PHI) were described as an independent marker of rapid disease onset, more robust than peak viremia or CD4 cell nadir. IP-10 enhances the recruitment of CXCR3+ cells, which include major HIV-target cells, raising the question if it promotes the establishment of viral reservoirs. We analyzed data from four cohorts of HIV+ patients, allowing us to study IP-10 levels before infection (Amsterdam cohort), as well as during controlled and uncontrolled viremia (ANRS cohorts).

Plasmacytoid Dendritic Cell Infection and Sensing Capacity during Pathogenic and Nonpathogenic Simian Immunodeficiency Virus Infection.

Unlabelled: Human immunodeficiency virus (HIV) in humans and simian immunodeficiency virus (SIV) in macaques (MAC) lead to chronic inflammation and AIDS. Natural hosts, such as African green monkeys (AGM) and sooty mangabeys (SM), are protected against SIV-induced chronic inflammation and AIDS. Here, we report that AGM plasmacytoid dendritic cells (pDC) express extremely low levels of CD4, unlike MAC and human pDC.

Modulation of type I interferon-associated viral sensing during acute simian immunodeficiency virus infection in African green monkeys.

Unlabelled: Natural hosts of simian immunodeficiency virus (SIV), such as African green monkeys (AGMs), do not progress to AIDS when infected with SIV. This is associated with an absence of a chronic type I interferon (IFN-I) signature. It is unclear how the IFN-I response is downmodulated in AGMs.

Phenotype alterations in regulatory T-cell subsets in primary HIV infection and identification of Tr1-like cells as the main interleukin 10-producing CD4+ T cells.

Background: Conventional regulatory T cells (Tregs) can suppress human immunodeficiency virus type 1 (HIV-1)-specific immune responses but cannot control immune activation in primary HIV infection. Here, we characterized Treg subsets, using recently defined phenotypic delineation, and analyzed the relative contribution of cell subsets to the production of immunosuppressive cytokines in primary HIV infection.

Methods: In a longitudinal prospective study, ex vivo phenotyping of fresh peripheral blood mononuclear cells from patients with primary HIV infection was performed at baseline and month 6 of follow-up to characterize Treg subsets, immune activation, and cytokine production in isolated CD4(+) T cells.

Innate immune responses and rapid control of inflammation in African green monkeys treated or not with interferon-alpha during primary SIVagm infection.

Chronic immune activation (IA) is considered as the driving force of CD4(+) T cell depletion and AIDS. Fundamental clues in the mechanisms that regulate IA could lie in natural hosts of SIV, such as African green monkeys (AGMs). Here we investigated the role of innate immune cells and IFN-α in the control of IA in AGMs.

The Th17/Treg ratio, IL-1RA and sCD14 levels in primary HIV infection predict the T-cell activation set point in the absence of systemic microbial translocation.

Impairment of the intestinal barrier and subsequent microbial translocation (MT) may be involved in chronic immune activation, which plays a central role in HIV pathogenesis. Th17 cells are critical to prevent MT. The aim of the study was to investigate, in patients with primary HIV infection (PHI), the early relationship between the Th17/Treg ratio, monocyte activation and MT and their impact on the T-cell activation set point, which is known to predict disease progression.

Acute plasma biomarkers of T cell activation set-point levels and of disease progression in HIV-1 infection.

T cell activation levels, viral load and CD4(+) T cell counts at early stages of HIV-1 infection are predictive of the rate of progression towards AIDS. We evaluated whether the inflammatory profile during primary HIV-1 infection is predictive of the virological and immunological set-points and of disease progression. We quantified 28 plasma proteins during acute and post-acute HIV-1 infection in individuals with known disease progression profiles.

Level of double negative T cells, which produce TGF-β and IL-10, predicts CD8 T-cell activation in primary HIV-1 infection.

Objective: Persistent immune activation plays a central role in the pathogenesis of HIV disease. Besides natural regulatory T cells (nTregs), 'double negative' T cells shown to exhibit regulatory properties could be involved in the control of harmful immune activation. The aim of this study was to analyze, in patients with primary HIV infection (PHI), the relationship between CD4(+)CD25(+)CD127(low)FoxP3(+) nTregs or CD3(+)CD4(-)CD8(-) double negative T cells and systemic immune activation.

Nonpathogenic SIV infection of African green monkeys induces a strong but rapidly controlled type I IFN response.

African green monkeys (AGMs) infected with the AGM type of SIV (SIVagm) do not develop chronic immune activation and AIDS, despite viral loads similar to those detected in humans infected with HIV-1 and rhesus macaques (RMs) infected with the RM type of SIV (SIVmac). Because chronic immune activation drives progressive CD4+ T cell depletion and immune cell dysfunctions, factors that characterize disease progression, we sought to understand the molecular basis of this AGM phenotype. To this end, we longitudinally assessed the gene expression profiles of blood- and lymph node-derived CD4+ cells from AGMs and RMs in response to SIVagm and SIVmac infection, respectively, using a genomic microarray platform.

Functional Epstein-Barr virus reservoir in plasma cells derived from infected peripheral blood memory B cells.

The Epstein-Barr virus (EBV) causes infectious mononucleosis, establishes latency in resting memory B lymphocytes, and is involved in oncogenesis through poorly understood mechanisms. The EBV lytic cycle is initiated during plasma cell differentiation by mRNAs transcripts encoded by BZLF1, which induce the synthesis of EBV proteins such as the immediate-early antigen ZEBRA and the late membrane antigen gp350. Therefore, we assessed the capacity of circulating EBV-infected B lymphocytes from healthy EBV-seropositive subjects to enter and complete the EBV lytic cycle.

Long-term persistence of memory B cells specific for hepatitis B surface antigen in HIV-1-infected patients.

To investigate the maintenance of long-term memory B cells specific for hepatitis B surface antigen (HBsAg), purified blood B cells were polyclonally stimulated and cells secreting antibodies directed to HBsAg (HBs-SC) enumerated by ELISpot. HBs-SC were found in 18/20 HIV-1-infected patients with either natural or vaccinal immunity to hepatitis B virus, including six subjects with serum anti-hepatitis B surface antibody levels less than 10 mIU/ml. A lower number of HBs-SC was found in HBsAg-vaccinated patients compared with vaccinated controls.

Detection of memory B lymphocytes specific to hepatitis B virus (HBV) surface antigen (HBsAg) from HBsAg-vaccinated or HBV-immunized subjects by ELISPOT assay.

To improve the investigation of the role of human memory B lymphocytes following hepatitis B virus (HBV) infection or vaccination, we developed a method to characterize circulating memory B cells specific to hepatitis B surface antigen (HBsAg). Our approach combined: (1) purification of CD19+ cells, (2) CD40-CD40L polyclonal stimulation, and (3) enumeration of memory B cells differentiated into anti-HBs antibody (Ab)-secreting cells (HBs-SCs) by a HBs-ELISPOT assay. In this way, HBs-SCs were detected in 17 HBsAg-vaccinated and nine HBV-immunized subjects including four individuals with serum anti-HBs Ab levels < 10 mIU/ml, but not in six controls.

Detection of a large T-cell reservoir able to replicate HIV-1 actively in breast milk.

In breast milk and paired blood samples of nine HIV-1-infected lactating women, we undertook a study to detect a CD4 T-cell reservoir and to investigate its capacity to enter viral production after activation. Breast milk-infected CD4 T cells have a greater capacity to produce viral particles actively than blood CD4 T cells. This observation may explain the apparent paradox of a transmissible viral infection from a body fluid with a low viral concentration.

Human immunodeficiency virus type 1 (HIV-1) antigen secretion by latently infected resting CD4+ T lymphocytes from HIV-1-infected individuals.

In resting CD4(+) T lymphocytes harboring human immunodeficiency virus type 1 (HIV-1), replication-competent virus persists in patients responding to highly active antiretroviral therapy (HAART). This small latent reservoir represents between 10(3) and 10(7) cells per patient. However, the efficiency of HIV-1 DNA-positive resting CD4(+) T cells in converting to HIV-1-antigen-secreting cells (HIV-1-Ag-SCs) after in vitro CD4(+)-T-cell polyclonal stimulation has not been satisfactorily evaluated.