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Dive into the research topics where François Simon is active.

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Featured researches published by François Simon.


Nature Medicine | 1998

Identification of a new human immunodeficiency virus type 1 distinct from group M and group O

François Simon; Philippe Mauclère; Pierre Roques; Ibtissam Loussert-Ajaka; Michaela Müller-Trutwin; Sentob Saragosti; Marie Claude Georges-Courbot; Françoise Barré-Sinoussi; Françoise Brun-Vézinet

A highly divergent HIV-1 isolate, designated YBF 30, was obtained in 1995 from a 40-year-old Cameroonian woman with AIDS. Depending on the genes studied, phylogenetic analysis showed that YBF30 branched either with SIVcpz-gab or between SIVcpz-gab and HIV-1 group M. The structural genes and tat, vpr, and nef of YBF30 are approximately equidistant from those of HIV-1 group M and SIVcpz-gab. In contrast, vif and rev are closer to HIV-1 group M, and vpu is highly divergent. Using a YBF30 V3 loop peptide enzyme immunoassay, we screened 700 HIV-1-positive sera collected in Cameroon; three reacted strongly with the YBF30 peptides and one was confirmed as being related to YBF30 by genetic analysis of a pol fragment. YBF30 is as distinct from SIVcpz-gab as it is from HIV-1 group M and can thus be considered as the prototype strain of a new human immunodeficiency virus group.


Nature Medicine | 2009

A new human immunodeficiency virus derived from gorillas.

Jean-Christophe Plantier; Marie Leoz; Jonathan E. Dickerson; Fabienne De Oliveira; François Cordonnier; Véronique Lemée; Florence Damond; David Robertson; François Simon

We have identified a new human immunodeficiency virus in a Cameroonian woman. It is closely related to gorilla simian immunodeficiency virus (SIVgor) and shows no evidence of recombination with other HIV-1 lineages. This new virus seems to be the prototype of a new HIV-1 lineage that is distinct from HIV-1 groups M, N and O. We propose to designate it HIV-1 group P.


Journal of Clinical Investigation | 2005

Antiinflammatory profiles during primary SIV infection in African green monkeys are associated with protection against AIDS

Christopher Kornfeld; Mickaël J.-Y. Ploquin; Ivona Pandrea; Abdourahmane Faye; Richard Onanga; Cristian Apetrei; Virginie Poaty-Mavoungou; Pierre Rouquet; Jérôme Estaquier; Lorenzo Mortara; Jean-François Desoutter; Cécile Butor; Roger Le Grand; Pierre Roques; François Simon; Françoise Barré-Sinoussi; Ousmane M. Diop; Michaela Müller-Trutwin

T cell activation levels in HIV infection are predictive of AIDS progression. We searched for the immunological correlates of protection against disease progression by studying the early stages of nonpathogenic SIV infection in African green monkeys (SIVagm). The African green monkeys (AGMs) displayed high peak viremias and a transient decline in levels of blood CD4(+) and CD8(+) T cells between days 5 and 17 after infection. A concomitant increase in levels of CD4(+)DR(+), CD8(+)DR(+), and CD8(+)CD28(-) cells was detected. After the third week, T cell activation returned to baseline levels, which suggested a protective downregulation of T cell activation. A very early (24 hours after infection) and strong induction of TGF-beta1 and FoxP3 expression was detected and correlated with increases in levels of CD4(+)CD25(+) and CD8(+)CD25(+) T cells. This was followed by a significant increase in levels of IL-10, whereas IFN-gamma gene upregulation was more transient, and levels of TNF-alpha and MIP-1alpha/beta transcripts did not increase in either blood or tissues. The profiles were significantly different during primary SIV infection in macaques (SIVmac); that is, there was a delayed increase in IL-10 levels accompanied by moderate and persistent increases in TGF-beta levels. Together, our data show that SIVagm infection is associated with an immediate antiinflammatory environment and suggest that TGF-beta may participate in the generation of Tregs, which may prevent an aberrant chronic T cell hyperactivation.


The Lancet | 1994

HIV-1/HIV-2 seronegativity in HIV-1 subtype 0 infected patients

I. Loussert-Ajaka; Françoise Brun-Vézinet; François Simon; T.D. Ly; M.L. Chaix; Sentob Saragosti; A.M. Couroucé; D. Ingrand

Nine patients with atypical HIV-1 western blot profiles were diagnosed as having HIV-1 subtype O infection. All the patients were living in France; eight originated from Cameroon and one from France. Lymphocyte DNA amplification by the polymerase chain reaction was only positive when HIV-1 subtype O specific primers were used. Preliminary sequence analysis of amplified products and serological reactivity against a specific subtype O synthetic env peptide confirmed HIV-1 subtype O infection. HIV-1/HIV-2 enzyme-linked immunosorbent assays, especially those based on env peptides or on the sandwich format, can be negative in HIV-1 subtype O infection.


AIDS | 1993

Cellular and plasma viral load in patients infected with HIV-2

François Simon; Matheron S; Tamalet C; Loussert-Ajaka I; Bartczak S; Pépin Jm; Dhiver C; Gamba E; Elbim C; Gastaut Ja

ObjectiveTo determine circulating viral load in HIV-2-infected individuals. MethodsViral load was determined in 40 HIV-2-infected adults using standardized quantitative cell and qualitative plasma viraemia assays. We also tested for proviral HIV-2 DNA using single and nested polymerase chain reaction (PCR) in fresh lymphocytes from 27 subjects. The results were compared, on the basis of the CD4+ lymphocyte count, with our published data for HIV-1 infection. ResultsHIV-2 was isolated from peripheral blood mononuclear cells (PBMC) from 19 individuals and plasma from four patients. The rate of cell and plasma viraemia positivity correlated with the CD4+ cell count and HIV-2 virus load increased as the CD4+ cell count fell. The cellular HIV-2 load in the patients with a CD4+ count<200


Journal of Virology | 2000

env Sequences of Simian Immunodeficiency Viruses from Chimpanzees in Cameroon Are Strongly Related to Those of Human Immunodeficiency Virus Group N from the Same Geographic Area

Sylvie Corbet; Michaela Müller-Trutwin; Pierre Versmisse; Séverine Delarue; Ahidjo Ayouba; John Lewis; Søren Brunak; Paul M. V. Martin; Françoise Brun-Vézinet; François Simon; Françoise Barré-Sinoussi; Philippe Mauclère


PLOS ONE | 2010

Sensitivity of five rapid HIV tests on oral fluid or finger-stick whole blood: a real-time comparison in a healthcare setting.

Juliette Pavie; Anne Rachline; Bénédicte Loze; Laurence Niedbalski; Constance Delaugerre; Eric Laforgerie; Jean-Christophe Plantier; Willy Rozenbaum; Sylvie Chevret; Jean-Michel Molina; François Simon

106/l was similar to reported values for HIV-1, but the HIV-2 isolation rate from the plasma of these individuals was significantly lower than for HIV-1. When the CD4+ count was between 200 and 500


AIDS | 1996

Lack of screening test sensitivity during HIV-1 non-subtype B seroconversions

Cristian Apetrei; Ibtissam Loussert-Ajaka; Diane Descamps; Florence Damond; Sentob Saragosti; Françoise Brun-Vézinet; François Simon


AIDS | 2000

HIV-1 diversity in France, 1996-1998.

Elisabeth Couturier; Florence Damond; Pierre Roques; Hervé Fleury; Francis Barin; Jean-Baptiste Brunet; Françoise Brun-Vézinet; François Simon

106/l, the rate of HIV-2 isolation from plasma and the cellular virus load were both significantly lower than for HIV-1. When the CD4+ count was > 500


AIDS Research and Human Retroviruses | 2001

Synthetic Peptide Strategy for the Detection of and Discrimination among Highly Divergent Primate Lentiviruses

François Simon; Sandrine Souquière; Florence Damond; Anfumbou Kfutwah; Maria Makuwa; Eric Leroy; Pierre Rouquet; Jean-Luc Berthier; Jacques Rigoulet; Alexis Lecu; Ivona Pandrea; Jean C. Plantier; Françoise Barré-Sinoussi; Pierre Roques; Michaela Müller-Trutwin; Cristian Apetrei

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Francis Barin

François Rabelais University

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