Publications by authors named "Florence Buseyne"

Foamy viruses (FVs) constitute a subfamily of retroviruses. Their envelope (Env) glycoprotein drives the merger of viral and cellular membranes during entry into cells. The only available structures of retroviral Envs are those from human and simian immunodeficiency viruses from the subfamily of orthoretroviruses, which are only distantly related to the FVs.

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Human immunodeficiency virus 1 (HIV-1) infection is characterized by a dynamic and persistent state of viral replication that overwhelms the host immune system in the absence of antiretroviral therapy (ART). The impact of prolonged treatment on the antiviral efficacy of HIV-1-specific CD8 T cells has nonetheless remained unknown. Here, we used single-cell technologies to address this issue in a cohort of aging individuals infected early during the pandemic and subsequently treated with continuous ART.

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Article Synopsis
  • - Infection with simian foamy viruses (SFVs) can result in lifelong infections in humans but typically do not cause severe disease or human-to-human transmission, making them an interesting case study for zoonotic retroviruses.
  • - Researchers studied neutralizing antibodies (nAbs) in SFV-infected individuals from Central Africa, focusing on the viral envelope protein's variable regions, which are crucial for nAb targeting and do not exhibit major immune escape mechanisms.
  • - Three primary regions crucial for nAb binding were identified, and they play a role in preventing the virus from changing shape or binding to human cells, effectively blocking infection.
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The surface envelope glycoprotein (Env) of all retroviruses mediates virus binding to cells and fusion of the viral and cellular membranes. A structure-function relationship for the HIV Env that belongs to the Orthoretrovirus subfamily has been well established. Structural information is however largely missing for the Env of Foamy viruses (FVs), the second retroviral subfamily.

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Article Synopsis
  • Zoonotic simian foamy viruses (SFV) lead to lifelong infections in humans but do not cause severe health issues or human-to-human transmission.
  • The study investigated the immune response of SFV-infected individuals, focusing on their ability to produce neutralizing antibodies against both cell-free virus and potential cell-to-cell transmission.
  • Despite finding that these antibodies can bind to the infected cells, the research concluded that they do not prevent the cell-to-cell spread of SFV, indicating different mechanisms of viral transmission.
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Background: Early combined antiretroviral therapy (cART) limits the total HIV-DNA load in children. However, data on its impact in older children and adolescents remain scarce. This study compares HIV reservoirs in children (5-12 years) and adolescents (13-17 years) who started cART <6 months (early [E-] group) or >2 years (late [L-] group).

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Article Synopsis
  • Early initiation of antiretroviral therapy (ART) in HIV-1-infected infants shows a positive impact on immune system health, specifically CD4 and CD8 T lymphocytes, but the effects in older children and adolescents need more study.
  • The ANRS-EP59-CLEAC study examined 27 children and 9 adolescents who started ART early compared to 19 children and 21 adolescents who started later, revealing that early treatment leads to higher CD8 T cell percentages.
  • Overall, while early ART benefits CD8 T cells significantly, the impact on CD4 T cells is less pronounced, suggesting late-treated pediatric patients can still effectively counteract CD4 T-cell loss through thymus production.
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Simian foamy viruses (SFVs) are complex retroviruses that are widespread throughout nonhuman primates. SFVs can also be transmitted to humans, mostly through bites. We previously observed that primary zoonotic gorilla SFV strains grow much more slowly than laboratory-adapted chimpanzee strains.

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Background: Zoonotic simian foamy viruses (SFVs) establish persistent infections in humans, for whom the long-term consequences for health are poorly described. In this study, we aimed to characterize blood-cell phenotypes and plasma biomarkers associated with gorilla SFV infection in humans.

Methods: We used a case-control design to compare 15 Cameroonian hunters infected with gorilla SFV (cases) to 15 controls matched for age and ethnicity.

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Cross-species transmission of simian foamy viruses (SFVs) from nonhuman primates (NHPs) to humans is currently ongoing. These zoonotic retroviruses establish lifelong persistent infection in their human hosts. SFV are apparently nonpathogenic , with ubiquitous tropism.

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The 12 International Foamy Virus Conference took place on August 30⁻31, 2018 at the Technische Universität Dresden, Dresden, Germany. The meeting included presentations on current research on non-human primate and non-primate foamy viruses (FVs; also called spumaretroviruses) as well as keynote talks on related research areas in retroviruses. The taxonomy of foamy viruses was updated earlier this year to create five new genera in the subfamily, , based on their animal hosts.

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Background: Nuclear localization of Gag is a property shared by many retroviruses and retrotransposons. The importance of this stage for retroviral replication is still unknown, but studies on the Rous Sarcoma virus indicate that Gag might select the viral RNA genome for packaging in the nucleus. In the case of Foamy viruses, genome encapsidation is mediated by Gag C-terminal domain (CTD), which harbors three clusters of glycine and arginine residues named GR boxes (GRI-III).

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Background: A spillover of simian foamy virus (SFV) to humans, following bites from infected nonhuman primates (NHPs), is ongoing in exposed populations. These retroviruses establish persistent infections of unknown physiological consequences to the human host.

Methods: We performed a case-control study to compare 24 Cameroonian hunters infected with gorilla SFV and 24 controls matched for age and ethnicity.

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Spumaretroviruses, commonly referred to as foamy viruses, are complex retroviruses belonging to the subfamily Spumaretrovirinae, family Retroviridae, which naturally infect a variety of animals including nonhuman primates (NHPs). Additionally, cross-species transmissions of simian foamy viruses (SFVs) to humans have occurred following exposure to tissues of infected NHPs. Recent research has led to the identification of previously unknown exogenous foamy viruses, and to the discovery of endogenous spumaretrovirus sequences in a variety of host genomes.

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Background: Gag-specific T lymphocytes play a key role in the control of human immunodeficiency virus (HIV) replication. Their restoration will be important for future reservoir targeting strategies. In this study, we aimed to identify immune correlates of Gag-specific CD8 T-cell proliferation in youths with perinatally acquired HIV-1 infection.

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The Eleventh International Foamy Virus Conference took place on 9-10 June 2016 at the Institut Pasteur, Paris, France. The meeting reviewed progress on foamy virus (FV) research, as well as related current topics in retrovirology. FVs are complex retroviruses that are widespread in several animal species.

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In perinatally HIV-1-infected youths living in France, we previously reported that Gag-specific CD4 and CD8 T cell proliferation is more frequently detected in patients of black ethnicity than in those of other ethnicities. We observed that black patients had higher levels of dendritic cells (DCs) than other patients. We aimed at studying the association of DC levels with Gag-specific T cell proliferation.

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The majority of currently identified simian foamy virus (SFV)-infected Cameroonian and Gabonese individuals harbor SFV from the gorilla lineage. We constructed an indicator cell line for the quantification of gorilla SFVs, in which the U3 sequence of a gorilla SFV directs the expression of the β-galactosidase protein. The gorilla foamy virus activated β-galactosidase (GFAB) cells efficiently quantified two zoonotic primary gorilla isolates and SFVs from three chimpanzee subspecies.

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The ANRS-EP38-IMMIP study aimed to provide a detailed assessment of the immune status of perinatally infected youths living in France. We studied Gag-specific CD4 and CD8 T-cell proliferation and the association between the proliferation of these cells, demographic factors and HIV disease history. We included 93 youths aged between 15 and 24 years who had been perinatally infected with HIV.

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Unlabelled: Simian foamy virus (SFV) is a ubiquitous retrovirus in nonhuman primates (NHPs) that can be transmitted to humans, mostly through severe bites. In the past few years, our laboratory has identified more than 50 hunters from central Africa infected with zoonotic SFVs. Analysis of the complete sequences of five SFVs obtained from these individuals revealed that env was the most variable gene.

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For the past two decades, scientists from around the world, working on different aspects of foamy virus (FV) research, have gathered in different research institutions almost every two years to present their recent results in formal talks, to discuss their ongoing studies informally, and to initiate fruitful collaborations. In this report we review the 2014 anniversary conference to share the meeting summary with the virology community and hope to arouse interest by other researchers to join this exciting field. The topics covered included epidemiology, virus molecular biology, and immunology of FV infection in non-human primates, cattle, and humans with zoonotic FV infections, as well as recent findings on endogenous FVs.

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