Superior control of HIV-1 replication by CD8+T cells is reflected by their avidity, polyfunctionality, and clonal turnover

The key attributes of CD8+ T cell protective immunity in human immunodeficiency virus (HIV) infection remain unclear. We report that CD8+ T cell responses specific for Gag and, in particular, the immunodominant p24 epitope KK10 correlate with control of HIV-1 replication in human histocompatibility leukocyte antigen (HLA)–B27 patients. To understand further the nature of CD8+ T cell–mediated antiviral efficacy, we performed a comprehensive study of CD8+ T cells specific for the HLA-B27–restricted epitope KK10 in chronic HIV-1 infection based on the use of multiparametric flow cytometry together with molecular clonotypic analysis and viral sequencing. We show that B27-KK10–specific CD8+ T cells are characterized by polyfunctional capabilities, increased clonal turnover, and superior functional avidity. Such attributes are interlinked and constitute the basis for effective control of HIV-1 replication. These data on the features of effective CD8+ T cells in HIV infection may aid in the development of successful T cell vaccines

Rotavirus Rearranged Genomic RNA Segments Are Preferentially Packaged into Viruses Despite Not Conferring Selective Growth Advantage to Viruses

The rotavirus (RV) genome consists of 11 double-stranded RNA segments. Sometimes, partial sequence duplication of an RNA segment leads to a rearranged RNA segment. To specify the impact of rearrangement, the replication efficiencies of human RV with rearranged segments 7, 11 or both were compared to these of the homologous human wild-type RV (wt-RV) and of the bovine wt-RV strain RF. As judged by viral growth curves, rotaviruses with a rearranged genome (r-RV) had no selective growth advantage over the homologous wt-RV. In contrast, r-RV were selected over wt-RV during competitive experiments (i.e mixed infections between r-RV and wt-RV followed by serial passages in cell culture). Moreover, when competitive experiments were performed between a human r-RV and the bovine wt-RV strain RF, which had a clear growth advantage, rearranged segments 7, 11 or both always segregated in viral progenies even when performing mixed infections at an MOI ratio of 1 r-RV to 100 wt-RV. Lastly, bovine reassortant viruses that had inherited a rearranged segment 7 from human r-RV were generated. Although substitution of wt by rearranged segment 7 did not result in any growth advantage, the rearranged segment was selected in the viral progenies resulting from mixed infections by bovine reassortant r-RV and wt-RV, even for an MOI ratio of 1 r-RV to 107 wt-RV. Lack of selective growth advantage of r-RV over wt-RV in cell culture suggests a mechanism of preferential packaging of the rearranged segments over their standard counterparts in the viral progeny

Etude des caractéristiques immunologiques et virologiques associées à la guérison de l'infection par le virus de l'hépatite C au cours d'une infection par le VIH

La co-infection par le VIH et le virus de l hépatite C entraine un passage plus fréquent à la chronicité de l'hépatite, une sévérité accrue et une moindre efficacité du traitement. Nous avons préalablement montré que la co-infection VIH participe à l'augmentation de la charge virale VHC, facteur péjoratif pour l efficacité du traitement. Notre travail avait pour objectif de mieux caractériser sur le plan immunologique et virologique la co-infection VIH, en particulier dans la phase aiguë de l'hépatite. Parmi une population VIH ayant des pratiques à risque, nous avons constitué et étudié de façon prospective, une cohorte de 38 patients en phase d hépatite C aiguë. L'évaluation d'un nouveau test de dépistage associant la détection de l'antigène et des anticorps anti-VHC nous a permis de proposer une stratégie optimale pour le suivi des patients VIH à risque d infection VHC. Nous avons observé que l hépatite C chez les co-infectés VIH est caractérisée par un faible taux de guérison spontanée (9%) et de faibles réponses immunes cellulaires spécifiques du VHC, médiées principalement par des cellules T CD4 de type effecteur-mémoire. Ces cellules spécifiques, rares dans le sang périphériques, ont pu être ainsi caractérisées après expansion in vitro. Nous avons montré un caractère favorable potentiel des réponses immunes anti-VHC dans l évolution spontanée ou sous traitement. Les altérations immunes liées au VIH affectent la mise en place de l immunité anti-VHC cellulaire et humorale, mais pas l efficacité du traitement du VHC lorsqu il est instauré précocement. Ces arguments plaident en faveur d'un diagnostic et d'une proposition de traitement anti-VHC les plus précoces possiblesPARIS-BIUSJ-Thèses (751052125) / SudocPARIS-BIUSJ-Physique recherche (751052113) / SudocSudocFranceF

Etude des réponses immunes contre le virus de l'immunodéficience humaine médiées par les lymphocytes T CD8+ dans la cohorte des patients Asymptomatiques à long terme

CHATENAY M.-PARIS 11-BU Pharma. (920192101) / SudocSudocFranceF

Impact of Radiochemotherapy on Immune Cell Subtypes in High-Grade Glioma Patients

Glioblastoma is a dreadful disease with very poor prognosis, median overall survival being <2 years despite standard-of-care treatment. This has led to the development of alternative strategies, among which immunotherapy is being actively tested. In particular, many clinical trials of therapeutic vaccination using peptides or tumor cells are ongoing. A major issue in implementing therapeutic vaccines in patients with high-grade glioma is that immune responses have to be elicited in the context of immunosuppressive treatments. Indeed, radiotherapy, chemotherapy, and steroids, which are part of the standard of care for patients with glioblastoma, are known to deplete leukocytes. Whether lymphopenia is beneficial or detrimental to elicitation of efficient immune responses is still debated. Here, in order to determine the impact of standard radiochemotherapy on immune cell subsets, we analyzed the phenotype and function of immune populations in 25 patients with high-grade glioma along concomitant radiochemotherapy and adjuvant chemotherapy with temozolomide. Thirteen healthy individuals were studied along the same period. We show that absolute T and B cell counts are reduced upon concomitant radiochemotherapy. Importantly, T cell counts were not restored long-term after discontinuation of treatment. In addition, the percentage of T regulatory cells among CD4 T cells was increased during the same period and was not decreased upon treatment discontinuation. Finally, we show that the ability of T cells to proliferate is transiently reduced after concomitant radiochemotherapy but is restored at the time of adjuvant TMZ cycles. Although not experimentally validated, transient reduction in proliferation associated with strong lymphopenia during radiochemotherapy may suggest that vaccine-induced T cell stimulation would be suboptimal in that period and that therapeutic vaccination should be performed outside radiochemotherapy administration. In addition, strategies aiming at depleting Treg cells should be implemented in future trials

Differential Performance of the FilmArray Meningitis/Encephalitis Assay To Detect Bacterial and Viral Pathogens in Both Pediatric and Adult Populations

Based on our comparative analysis of performances of the diagnostic assays, we propose an algorithm for the use of both syndromic and specific assays, for an optimal care of the meningitis/encephalitis threat in adult and pediatric patients. , ABSTRACT Meningitis/encephalitis (ME) syndromic diagnostic assays can be applied for the rapid one-step detection of the most common pathogens in cerebrospinal fluid (CSF). However, the comprehensive performance of multiplex assays is still under evaluation. In our multisite university hospital of eastern Paris, France, ME syndromic testing has been gradually implemented since 2017 for patients with neurological symptoms presenting to an adult or pediatric emergency unit. We analyzed the results from the BioFire FilmArray ME panel versus standard routine bacteriology and virology techniques, together with CSF cytology and clinical data, over a 2.5-year period to compare the diagnostic accuracy of the FilmArray ME panel to that of the reference methods. In total, 1,744 CSF samples from 1,334 pediatric and 336 adult patients were analyzed. False-positive (mostly bacterial) and false-negative (mostly viral) cases were deciphered with the help of clinical data. The performance of the FilmArray ME panel in our study was better for bacterial detection (specificity\,>99%, sensitivity 100%) than viral detection (specificity\,>99%, sensitivity 75% for herpes simplex virus 1 [HSV-1] and 89% for enterovirus), our study being one of the largest, to date, concerning enteroviruses. The use of a threshold of 10 leukocytes/mm 3 considerably increased the positive agreement between the results of the FilmArray ME panel and the clinical features, especially for bacterial pathogens, for which agreement increased from 58% to 87%, avoiding two-thirds of inappropriate testing. Based on this analysis, we propose an algorithm for the use of both syndromic and specific assays for the optimal management of suspected meningitis/encephalitis in adult and pediatric patients. IMPORTANCE Based on our comparative analysis of performances of the diagnostic assays, we propose an algorithm for the use of both syndromic and specific assays, for an optimal care of the meningitis/encephalitis threat in adult and pediatric patients

Competitive experiments between bovine wt-RV and human r-RV.

<p>Competitive experiments were performed by co-infecting MA-104 cells by the bovine wt-RV RF and one of the human r-RV at an MOI ratio of 1∶1 (0.3 PFU/cell for each virus). The resulting cell culture lysates were serially propagated in MA-104 cells. RNA profiles of viral progenies resulting from mixed infections by wt-bovine RF virus and human r-RV M1 (A), M3 (B), M4 (C), or M2 (D). RNA profiles of wt-bovine RF and human r-RV show differences of mobility for 8 RNA segments (segments 1, 4–6, 8–11). I and Pn indicate the initial inoculum used for mixed infections and the passage number, respectively. Numbers indicate the location of RNA segments. Arrows indicate rearranged segments 7R, 7RΔ, and 11R.</p