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BackgroundZoonotic 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.MethodsWe used a case-control design to compare 15 Cameroonian hunters infected with gorilla SFV (cases) to 15 controls matched for age and ethnicity. A flow cytometry-based phenotypic study and quantification of plasma immune biomarkers were carried out on blood samples from all participants. Wilcoxon signed-rank tests were used to compare cases and controls.ResultsCases had a significantly higher percentage of CD8 T lymphocytes than controls (median, 17.6% vs 13.7%; P = .03) but similar levels of B, natural killer, and CD4 T lymphocytes. Cases also had a lower proportion of recent CD4 thymic emigrants (10.9% vs 18.6%, P = .05), a higher proportion of programmed death receptor 1 (PD-1) expressing memory CD4 T lymphocytes (31.7% vs 24.7%, P = .01), and higher plasma levels of the soluble CD163 scavenger receptor (0.84 vs .59 µg/mL, P = .003) than controls.ConclusionsWe show, for the first time, that chronic infection with SFV is associated with T lymphocyte differentiation and monocyte activation.

International audience; Cross-species transmission of simian foamy viruses (SFVs) from nonhu-man primates (NHPs) to humans is currently ongoing. These zoonotic retroviruses establish lifelong persistent infection in their human hosts. SFV are apparently non-pathogenic in vivo, with ubiquitous in vitro tropism. Here, we aimed to identify envelope B-cell epitopes that are recognized following a zoonotic SFV infection. We screened a library of 169 peptides covering the external portion of the envelope from the prototype foamy virus (SFVpsc_huHSRV.13) for recognition by samples from 52 Central African hunters (16 uninfected and 36 infected with chimpanzee, gorilla, or Cercopithecus SFV). We demonstrate the specific recognition of peptide N 96-V 110 located in the leader peptide, gp18 LP. Forty-three variant peptides with truncations, alanine substitutions, or amino acid changes found in other SFV species were tested. We mapped the epitope between positions 98 and 108 and defined six amino acids essential for recognition. Most plasma samples from SFV-infected humans cross-reacted with sequences from apes and Old World monkey SFV species. The magnitude of binding to peptide N 96-V 110 was significantly higher for samples of individuals infected with a chimpanzee or gorilla SFV than those infected with a Cercopithecus SFV. In conclusion, we have been the first to define an immunodomi-nant B-cell epitope recognized by humans following zoonotic SFV infection. IMPORTANCE Foamy viruses are the oldest known retroviruses and have been mostly described to be nonpathogenic in their natural animal hosts. SFVs can be transmitted to humans, in whom they establish persistent infection, like the simian lenti-and deltaviruses that led to the emergence of two major human pathogens, human immunodeficiency virus type 1 and human T-lymphotropic virus type 1. This is the first identification of an SFV-specific B-cell epitope recognized by human plasma samples. The immunodominant epitope lies in gp18 LP , probably at the base of the envelope trimers. The NHP species the most genetically related to humans transmitted SFV strains that induced the strongest antibody responses. Importantly, this epitope is well conserved across SFV species that infect African and Asian NHPs.

International audience; 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. A complete physical examination and blood test were performed for all participants. Logistic regression and Wilcoxon signed rank tests were used to compare cases and controls. Results. The cases had significantly lower levels of hemoglobin than the controls (median, 12.7 vs 14.4 g/dL; P = .01). Basophil levels were also significantly lower in cases than controls, with no differences for other leukocyte subsets. Cases had significantly higher urea, creatinine, protein, creatinine phosphokinase, and lactate dehydrogenase levels and lower bilirubin levels than controls. Cases and controls had similar frequencies of general, cutaneous, gastrointestinal, neurological, and cardiorespiratory signs. Conclusions. The first case-control study of apparently healthy SFV-infected Cameroonian hunters showed the presence of hematological abnormalities. A thorough clinical and laboratory workup is now needed to establish the medical relevance of these observations because more than half of cases had mild or moderate anemia. Clinical Trials Registration. NCT03225794.

International audience; 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. Primary gorilla SFVs replicated more slowly and at lower levels than primary chimpanzee SFVs. Analysis of previously described motifs of Tas proteins and U3 LTRs involved in viral gene synthesis revealed conservation of such motifs in Tas proteins from gorilla and chimpanzee SFVs, but little sequence homology in the LTR regions previously shown to interact with viral and cellular factors.

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. Furthermore, recombinant SFV strains, some of which involve sequences in the env gene, were recently identified. Here, we investigated the variability of the env genes of zoonotic SFV strains and searched for possible recombinants. We sequenced the complete env gene or its surface glycoprotein region (SU) from DNA amplified from the blood of (i) a series of 40 individuals from Cameroon or Gabon infected with a gorilla or chimpanzee foamy virus (FV) strain and (ii) 1 gorilla and 3 infected chimpanzees living in the same areas as these hunters. Phylogenetic analyses revealed the existence of two env variants among both the gorilla and chimpanzee FV strains that were present in zoonotic and NHP strains. These variants differ greatly (>30% variability) in a 753-bp-long region located in the receptor-binding domain of SU, whereas the rest of the gene is very conserved. Although the organizations of the Env protein sequences are similar, the potential glycosylation patterns differ between variants. Analysis of recombination suggests that the variants emerged through recombination between different strains, although all parental strains could not be identified. IMPORTANCE SFV infection in humans is a great example of a zoonotic retroviral infection that has not spread among human populations, in contrast to human immunodeficiency viruses (HIVs) and human T-lymphotropic viruses (HTLVs). Recombination was a major mechanism leading to the emergence of HIV. Here, we show that two SFV molecular envelope gene variants circulate among ape populations in Central Africa and that both can be transmitted to humans. These variants differ greatly in the SU region that corresponds to the part of the Env protein in contact with the environment. These variants may have emerged through recombination between SFV strains infecting different NHP species.

Background. Our aim was to study the impact of lifelong human immunodeficiency virus (HIV) disease history on the current immune and virological status of perinatally infected patients reaching adulthood. We evaluated blood cell–associated HIV DNA load as an indicator of cell-associated HIV reservoirs and an independent predictor of disease progression. Methods. The ANRS-EP38-IMMIP Study included 93 patients aged 15–24 years who were infected with HIV during the perinatal period. HIV DNA load was quantified by real-time polymerase chain reaction. Results. Eighty-five percent of patients were receiving highly active antiretroviral therapy (HAART), and HIV RNAwas undetectableintheplasmaof75%ofthesepatients.ThemedianHIV DNAloadwas 2.84(interquartilerange, 2.51–3.16) log10 copies per 10 6 peripheral blood mononuclear cells. In patients with viral suppression, HIV DNA load was independently associated with cumulative HIV RNA viremia over the last 5 years. HIV DNA load was negatively correlated with CD4 cell count in patients with active replication but not in those with undetectable HIV RNA. Conclusions. In perinatally infected youths who are successfully treated, sustained viral suppression is associated with a low HIV DNA load. The absence of association between current HIV DNA load and CD4 cell counts suggests that the unique physiological characteristics of pediatric infection persist after adolescence. Clinical Trials Registration. NCT01055873.

Simian foamy virus (SFV) is a retrovirus ubiquitous in non-human primates (NHPs) that can be transmitted to humans, mostly through severe bites. In the past few years, our laboratory identified more than 50 hunters from Central Africa infected with zoonotic SFVs. Analysis of SFV complete sequences obtained from 5 of these individuals had revealed that the env gene was the most variable one. Furthermore, recombinant SFV strains have been recently shown; some of them involved the env gene. This led us to investigate the env gene variability of zoonotic SFV strains, looking especially for possible recombinants. We sequenced the complete or the surface glycoprotein region (SU) of SFV env gene amplified from blood DNA of: 1) a series of 40 individuals from Cameroon or Gabon infected with a gorilla or chimpanzee FV strain; 2) one gorilla and 3 infected chimpanzees living in the same areas than the hunters. All sequences were aligned and analysed by phylogenetic (neighbour-joining and maximum likelihood) and recombinant detection methods (similarity plot and bootscan analysis, Recombination Detection Program). Phylogenetic analyses revealed the existence of two different env variants among both gorilla FV and chimpanzee FV strains. These were present in zoonotic as well as in NHP strains. These variants differ greatly (more than 30% variability) in a 750 bp long region located in the receptor binding domain of the SU; the rest of the gene is very conserved (less than 5% variability among strains from the same species). Within a given variant, protein sequences of the SU are very conserved and stable (non-synonymous/synonymous mutations ratio

HIV-specific CD8+ T lymphocytes participate in the control of viral replication in infected patients. These responses are of low intensity in young infants and are decreased by antiretroviral therapy. In the present study, we report on a recombinant Vaccinia virus (rVV)-based Elispot assay for the detection of HIV-specific CD8+ T cells immediately after isolation of peripheral blood mononuclear cells (PBMC). The rVV-based assay was highly sensitive; 48 out of 50 children had a positive response against the rVV encoding HIV Env-Gag-Pol antigen. Interferon-gamma was produced by CD8+ T cells, and CD14+/15+ cells were the main cell subset presenting antigens expressed by rVV. We observed that the cell input per well had a critical influence on the sensitivity of the assay. Results from the ex vivo Elispot assay correlated poorly with those of the 51Cr release assay performed after expansion of PBMC in vitro; thus, both assays gave information on different subsets and/or functions of the HIV-specific T cell response.

Ex vivo interferon (IFN)- gamma -producing CD8 T cells specific for human immunodeficiency virus (HIV) Env, Gag, and Pol antigens were measured in the peripheral blood of 55 children not receiving highly active antiretroviral therapy (HAART) and 70 children receiving HAART. In children not receiving HAART, the frequency of HIV-specific IFN- gamma -producing CD8 T cells was positively correlated with age and was not associated with plasma viral load or CD4 T cell levels. In children receiving HAART, the frequency of HIV-specific IFN- gamma -producing CD8 T cells was directly correlated with plasma viral load, and its association with age remained significant. In conclusion, the frequency of HIV-specific IFN- gamma -producing CD8 T cells in children is primarily determined by both age and plasma viral load.

International audience; Simian foamy viruses (SFV) are widespread retroviruses among non-human primates (NHP). SFV actively replicate in the oral cavity of NHP and can be transmitted to humans through NHP bites, in whom they establish a persistent infection. We aimed to study three major properties of these zoonotic retroviruses: replicative status, tropism and variability. In 14 hunters from Cameroon previously shown to be infected with a gorilla SFV strain, viral DNA could be detected by quantitative polymerase chain reaction in most samples of peripheral blood mononuclear cells (PBMCs) and saliva. The SFV DNA levels were 7.1±6.0 SFV DNA copies/105 cells in PBMCs and 2.4±4.3 SFV DNA copies/105 cells in saliva. In contrast, no SFV RNA was detected by qRT-PCR in either PBMCs or saliva. PBMCs populations (T4, T8, B, NK lymphocytes and monocytes) were sorted with magnetic beads before quantification of SFV DNA. Our preliminary results showed the presence of SFV DNA in all PBMCs populations at different levels. We finally assessed the viral diversity in vivo. Although intra-individual SFV genetic variation was low (

CD8+ T cells may play a beneficial role in human immunodeficiency virus (HIV)-infected patients by two mechanisms: HIV-specific cytotoxic activity and secretion of a soluble mediator(s) that inhibits HIV replication in vitro. Here we characterized both activities mediated by an HIV p24 gag -specific cytotoxic T lymphocyte (CTL) CD8+ clone derived from an HIV-infected patient. When the CTL clone was mixed with HIV-infected autologous CD4+ T cells, viral replication was suppressed. This viral inhibition was observed in heterologous CD4+ T cells and when CD8+ and CD4+ populations were separated by a semipermeable membrane, demonstrating the involvement of a diffusible factor(s). The lysis of autologous HIV-infected T cells was also detected. However, HIV suppression was more efficient when CD4+ and CD8+ T cells shared major histocompatibility complex alleles and were in direct contact. Thus, one and the same CD8+ T cell population can mediate both lysis of HIV-infected targets and nonlytic suppression of HIV replication. These results underline the multiple roles of CD8+ T lymphocytes in the suppression of HIV-infected cells.

Method A cross-sectional analysis of immune and viral parameters was performed on 44 HIV-infected children (median 7.8 yrs, 0.08-18.6) that were untreated at time of biological assessment. Frequency of IFN-γ producing CD8 lymphocytes in response to Env-Gag-Pol antigens was determined using the ELISPOT technique. HIV-RNA level was determined by PCR (monitor 1.5, Roche). HIV DNA level was determined in total PBMC, using real time PCR in LTR (ANRS method). Associations between quantitative variables were defined by Pearson's partial correlations. Partial correlation measures the strength of relationship between two variables, controlling for the effect of one or more other variables.

Simian foamy viruses (SFVs) are ancient and wide-spread complex-type retroviruses that have co-evolved with their non-human primate (NHP) species for millions of years. These viruses can be transmitted to humans, primarily through bites, leading to the establishment of a life-long persistent infection. Despite frequent zoonotic transmission of SFVs from NHPs to humans in Central Africa and Asia, no overt pathology or human-to-human transmission of SFVs have been reported yet. My host laboratory hypothesized that the immune system efficiently controls viral replication in zoonotically infected humans. They demonstrated that neutralizing antibodies (nAbs) are present at high titers in Central African hunters infected with gorilla and chimpanzee SFV strains. My colleagues showed that two viral genotypes are circulating among SFV-infected NHPs and humans. A variant region within the surface domain (SU) of the viral envelope glycoprotein (Env), termed SUvar, forms basis of the two genotypes. The receptor binding domain (RBD) overlaps the SUvar region. The nAbs strictly target the SUvar region on the SFV Env.I aimed to characterize nAb epitopes located within the SUvar region of SFV Env. To map nAb epitopes within SUvar, I performed neutralization assays in presence of recombinant SU proteins that compete with Env at the surface of viral particles for nAb binding. I used plasma samples from Central African hunters infected with gorilla SFVs and foamy viral vectors expressing SFV Env from each of the two genotypes. I generated mutant SU proteins by systematically deleting glycosylation sites, inserting glycans to disrupt epitopes and by swapping residues between the two genotypes.I have described that nAb epitopes have a genotype-specific location. Through collaborative work with the laboratory of Prof. Félix Rey who solved the crystal structure of a gorilla SFV RBD, I have discovered that most SFV-specific nAbs target epitopes located at the apex of Env, in particular three mobile loops located at the interface between protomers. Vectors with deleted loops were produced and bound to cells but were non-infectious, suggesting that nAbs target epitopes with functional importance. In addition, we found a second major epitope in the bottom part of the RBD targeted by nAbs from individuals infected by one of the two genotypes. This region is involved in binding to cells. My results suggest that SFV-specific nAbs could block viral entry either by preventing Env binding to the cell surface or by preventing conformational changes of the Env trimer and fusion of viral and cellular membranes. Collectively, my data support the role of nAbs in the control of viral replication and human-to-human transmission.; Les virus foamy simiens (VFS) sont des rétrovirus de type complexe anciens et très répandus. Ils ont évolué conjointement avec leur espèce hôte pendant des millions d'années. Ces virus peuvent être transmis à l'homme, principalement par des morsures, entraînant l'établissement d'une infection persistante. Malgré la transmission zoonotique fréquente des VFS des PNH aux humains en Afrique centrale et en Asie, aucune pathologie sévère ou transmission interhumaine des VFS n'a encore été décrite. Mon laboratoire a émis l'hypothèse que le système immunitaire contrôle efficacement la réplication virale chez les humains infectés par des zoonoses. Mes collègues ont démontré que des anticorps neutralisants (AcNs) sont présents à des titres élevés chez les chasseurs d'Afrique centrale infectés par des souches de VFS de gorille et de chimpanzé. Deux génotypes viraux circulent parmi les primates non humains (PNHs) et les hommes infectés par le VFS. Une région variante au sein du domaine de surface (SU) de la glycoprotéine d'enveloppe virale (Env), appelée SUvar, constitue la base des deux génotypes. Le domaine de liaison au récepteur (RBD, pour receptor binding domain) chevauche la région SUvar. Ces anticorps neutralisants ciblent strictement la région SUvar de l'Env du VFS.Mon objectif était de caractériser les épitopes reconnus par les AcN situés dans la région SUvar de l'Env du VFS. Pour cartographier les épitopes AcN au sein de la SUvar, j'ai réalisé des tests de neutralisation en présence de protéines SU recombinantes agissant comme compétiteurs de l’enveloppe des particules virales pour la liaison aux AcN. J'ai utilisé des échantillons de plasma provenant de chasseurs d'Afrique centrale infectés par le VFS du gorille et des vecteurs viraux foamy exprimant l'Env du VFS de l'un ou l'autre des deux génotypes. J'ai généré des protéines SU mutantes en supprimant systématiquement des sites de glycosylation, en insérant des sites de glycosylation pour modifier des épitopes et en échangeant des domaines entre les deux génotypes.J'ai montré que les épitopes neutralisants ont une localisation spécifique au génotype. Grâce à une collaboration avec le laboratoire du professeur Félix Rey qui a résolu une structure d'un RBD du VFS du gorille, j’ai pu montré que la plupart des AcNs spécifiques du VFS ciblent des épitopes situés à l'apex de Env, en particulier trois boucles mobiles situées à l'interface entre les protomères. Des vecteurs dont l’enveloppe est délétée pour chacune de ces boucles se fixent aux cellules mais sont non infectieux, ce qui suggère que les AcNs ciblent des épitopes ayant une importance fonctionnelle. De plus, nous avons trouvé un deuxième épitope majeur dans la partie inférieure du RBD ciblé par les AcNs provenant d'individus infectés par l'un des deux génotypes. Cette région est impliquée dans la fixation aux cellules. Mes résultats suggèrent que les AcNs spécifiques du VFS pourraient bloquer l'entrée du virus, soit en inhibant l’interaction entre Env et la surface de la cellule soit en empêchant le changement de conformation de Env permettant la fusion des membranes virale et cellulaire. Mes données confirment que les AcNs pourraient contribuer à contrôler la réplication virale et la transmission interhumaine des VFS.

International audience; BackgroundEarly 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 aims to compare HIV reservoirs in children (5-12 years) and adolescents (13-17 years) who started cART before 6 months (early (E-)group) or after 2 years old (late (L-)group). MethodsThe ANRS-EP59-CLEAC study prospectively enrolled 76 HIV-1 perinatally-infected patients who reached HIV-RNA

International audience; Human T-cell Lymphotropic Virus type 1 (HTLV-1) is a human retrovirus that infects at least 5–10 million people worldwide, and is the etiological agent of a lymphoproliferative malignancy; Adult T-cell Leukemia/Lymphoma (ATLL); and a chronic neuromyelopathy, HTLV-1 Associated Myelopathy/Tropical Spastic Paraparesis (HAM/TSP), as well as other inflammatory diseases such as infective dermatitis and uveitis. Besides sexual intercourse and intravenous transmission, HTLV-1 can also be transmitted from infected mother to child during prolonged breastfeeding. Some characteristics that are linked to mother-to-child transmission (MTCT) of HTLV-1, such as the role of proviral load, antibody titer of the infected mother, and duration of breastfeeding, have been elucidated; however, most of the mechanisms underlying HTLV-1 transmission during breast feeding remain largely unknown, such as the sites of infection and cellular targets as well as the role of milk factors. The present review focuses on the latest findings and current opinions and perspectives on MTCT of HTLV-1.