Unexpected Diversity of Cellular Immune Responses against Nef and Vif in HIV-1-Infected Patients Who Spontaneously Control Viral Replication

Background: HIV-1-infected individuals who spontaneously control viral replication represent an example of successful containment of the AIDS virus. Understanding the anti-viral immune responses in these individuals may help in vaccine design. However, immune responses against HIV-1 are normally analyzed using HIV-1 consensus B 15-mers that overlap by 11 amino acids. Unfortunately, this method may underestimate the real breadth of the cellular immune responses against the autologous sequence of the infecting virus. Methodology and Principal Findings: Here we compared cellular immune responses against nef and vif-encoded consensus B 15-mer peptides to responses against HLA class I-predicted minimal optimal epitopes from consensus B and autologous sequences in six patients who have controlled HIV-1 replication. Interestingly, our analysis revealed that three of our patients had broader cellular immune responses against HLA class I-predicted minimal optimal epitopes from either autologous viruses or from the HIV-1 consensus B sequence, when compared to responses against the 15-mer HIV-1 type B consensus peptides. Conclusion and Significance: This suggests that the cellular immune responses against HIV-1 in controller patients may be broader than we had previously anticipated.

Polymorphism of the Human Immunodeficiency Virus Type 1 in Brazil: Genetic Characterization of the nef Gene and Implications for Vaccine Design

Most of the Brazilian HIV-1 samples have been characterized based on the structural genes (env, gag and pol) and no data concerning the variability of the accessory genes such as nef have been available so far. Considering the role of the nef on virus biology and the inclusion of this region in some HIV/AIDS vaccine products under testing, the purpose of this study was to document the genetic diversity of the nef gene in third-four HIV-1 Brazilian samples previously subtyped based on the env C2-V3 region. Although only few non-subtype B samples have already been analyzed so far, the cytotoxic Tlymphocyte epitopes encoded in this region were relatively conserved among the subtypes, with some amino acid signatures mainly in the subtype C samples. Considering the increasing of the non-B HIV-1 subtypes worldwide, in special the subtype C, more data should be generated concerning the genetic and antigenic variability of these subtypes, as well as the study of the impact of such polymorphism in HIV/AIDS vaccine design and testing.

Soissons, cathédrale [Saint-Gervais-et-Saint-Protais], la nef [dégâts dus à la guerre] : [photographie de presse] / [Agence Rol]

Référence bibliographique : Rol, 55104

Soissons, cathédrale [Saint-Gervais-et-Saint-Protais], bas-côté de la nef [dégâts dus à la guerre] : [photographie de presse] / [Agence Rol]

Référence bibliographique : Rol, 55102

Soissons, la cathédrale [Saint-Gervais-et-Saint-Protais], la nef coupée en deux [dégâts dus à la guerre] : [photographie de presse] / [Agence Rol]

Référence bibliographique : Rol, 55112

Virological and Immunological Characterization of Novel NYVAC-Based HIV/AIDS Vaccine Candidates Expressing Clade C Trimeric Soluble gp140(ZM96) and Gag(ZM96)-Pol-Nef(CN54) as Virus-Like Particles.

The generation of vaccines against HIV/AIDS able to induce long-lasting protective immunity remains a major goal in the HIV field. The modest efficacy (31.2%) against HIV infection observed in the RV144 phase III clinical trial highlighted the need for further improvement of HIV vaccine candidates, formulation, and vaccine regimen. In this study, we have generated two novel NYVAC vectors, expressing HIV-1 clade C gp140(ZM96) (NYVAC-gp140) or Gag(ZM96)-Pol-Nef(CN54) (NYVAC-Gag-Pol-Nef), and defined their virological and immunological characteristics in cultured cells and in mice. The insertion of HIV genes does not affect the replication capacity of NYVAC recombinants in primary chicken embryo fibroblast cells, HIV sequences remain stable after multiple passages, and HIV antigens are correctly expressed and released from cells, with Env as a trimer (NYVAC-gp140), while in NYVAC-Gag-Pol-Nef-infected cells Gag-induced virus-like particles (VLPs) are abundant. Electron microscopy revealed that VLPs accumulated with time at the cell surface, with no interference with NYVAC morphogenesis. Both vectors trigger specific innate responses in human cells and show an attenuation profile in immunocompromised adult BALB/c and newborn CD1 mice after intracranial inoculation. Analysis of the immune responses elicited in mice after homologous NYVAC prime/NYVAC boost immunization shows that recombinant viruses induced polyfunctional Env-specific CD4 or Gag-specific CD8 T cell responses. Antibody responses against gp140 and p17/p24 were elicited. Our findings showed important insights into virus-host cell interactions of NYVAC vectors expressing HIV antigens, with the activation of specific immune parameters which will help to unravel potential correlates of protection against HIV in human clinical trials with these vectors. IMPORTANCE: We have generated two novel NYVAC-based HIV vaccine candidates expressing HIV-1 clade C trimeric soluble gp140 (ZM96) and Gag(ZM96)-Pol-Nef(CN54) as VLPs. These vectors are stable and express high levels of both HIV-1 antigens. Gag-induced VLPs do not interfere with NYVAC morphogenesis, are highly attenuated in immunocompromised and newborn mice after intracranial inoculation, trigger specific innate immune responses in human cells, and activate T (Env-specific CD4 and Gag-specific CD8) and B cell immune responses to the HIV antigens, leading to high antibody titers against gp140. For these reasons, these vectors can be considered vaccine candidates against HIV/AIDS and currently are being tested in macaques and humans.

Les clavecinistes français des XVIIe et XVIIIe siècles / d'Anglebert, d'Andrieu, J.- Ph. Rameau... [et al.], comp. ; Isabelle Nef, clav.

Comprend : Allemande, gavotte, menuet / J.- H. d'Anglebert, comp. ; Isabelle Nef, clav. ; Le ramage, Les amours, L'hymen / Jean-François Dandrieu, comp. ; Isabelle Nef, clav. ; L'entretien des muses / Jean-Philippe Rameau, comp. ; Isabelle Nef, clav. ; Chaconne / Louis Couperin, comp. ; Isabelle Nef, clav. ; Allemande, courante, sarabande / Jacques Champion de Chambonnières, comp. ; Isabelle Nef, clav. ; La rare / Jacques Champion de Chambonnières, comp. ; Isabelle Nef, clav. ; Musette / Louis Claude Daquin, comp. ; Isabelle Nef, clav. ; Tambourin / Louis Claude Daquin, comp. ; Isabelle Nef, clav. ; Les bergères / Louis Claude Daquin, comp. ; Isabelle Nef, clav. ; Chaconne / J.- H. d'Anglebert, comp. ; Isabelle Nef, clav. ; Les roseaux / François Couperin, comp. ; Isabelle Nef, clav. ; Les petits moulins à vent / François Couperin, comp. ; Isabelle Nef, clav.

Counteraction of HLA-C-mediated immune control of HIV-1 by Nef.

A host genetic variant (-35C/T) correlates with increased human leukocyte antigen C (HLA-C) expression and improved control of HIV-1. HLA-C-mediated immunity may be particularly protective because HIV-1 is unable to remove HLA-C from the cell surface, whereas it can avoid HLA-A- and HLA-B-mediated immunity by Nef-mediated down-modulation. However, some individuals with the protective -35CC genotype exhibit high viral loads. Here, we investigated whether the ability of HIV-1 to replicate efficiently in the "protective" high-HLA-C-expression host environment correlates with specific functional properties of Nef. We found that high set point viral loads (sVLs) were not associated with the emergence of Nef variants that had acquired the ability to down-modulate HLA-C or were more effective in removing HLA-A and HLA-B from the cell surface. However, in individuals with the protective -35CC genotype we found a significant association between sVLs and the efficiency of Nef-mediated enhancement of virion infectivity and modulation of CD4, CD28, and the major histocompatibility complex class II (MHC-II)-associated invariant chain (Ii), while this was not observed in subjects with the -35TT genotype. Since the latter Nef functions all influence the stimulation of CD4(+) T helper cells by antigen-presenting cells, they may cooperate to affect both the activation status of infected T cells and the generation of an antiviral cytotoxic T-lymphocyte (CTL) response. In comparison, different levels of viremia in individuals with the common -35TT genotype were not associated with differences in Nef function but with differences in HLA-C mRNA expression levels. Thus, while high HLA-C expression may generally facilitate control of HIV-1, Nef may counteract HLA-C-mediated immune control in some individuals indirectly, by manipulating T-cell function and MHC-II antigen presentation.

Threefolds with nef anticanonical bundles

In this paper we study the global structure of projective threefolds X whose anticanonical bundle K is nef.

"In vitro" study of the molecular mechanism of the "E.Coli" Hsp 70/Hsp40/NEF chaperone system and its interactions with ?-sinuclein

SUMMARY Under stressful conditions, mutant or post-translationally modified proteins may spontaneously misfold and form toxie species, which may further assemble into a continuum of increasingly large and insoluble toxic oligomers that may further condense into less toxic, compact amyloids in the cell Intracellular accumulation of aggregated proteins is a common denominator of several neurodegenerative diseases. To cope with the cytotoxicity induced by abnormal, aggregated proteins, cells have evolved various defence mechanisms among which, the molecular chaperones Hsp70. Hsp70 (DnaK in E. coii) is an ATPase chaperone involved in many physiological processes in the cell, such as assisting de novo protein folding, dissociating native protein oligomers and serving as pulling motors in the import of polypeptides into organelles. In addition, Hsp70 chaperones can actively solubilize and reactivate stable protein aggregates, such as heat- or mutation-induced aggregates. Hsp70 requires the cooperation of two other co-chaperones: Hsp40 and NEF (Nucleotide exchange factor) to fulfil its unfolding activity. In the first experimental section of this thesis (Chapter II), we studied by biochemical analysis the in vitro interaction between recombinant human aggregated α-synuclein (a-Syn oligomers) mimicking toxic a-Syn oligomers species in PD brains, with a model Hsp70/Hsp40 chaperone system (the E. coii DnaK/DnaJ/GrpE). We found that chaperone-mediated unfolding of two denatured model enzymes were strongly affected by α-Syn oligomers but, remarkably, not by monomers. This in vitro observed dysfunction of the Hsp70 chaperone system resulted from the sequestration of the Hsp40 proteins by the oligomeric α-synuclein species. In the second experimental part (Chapter III), we performed in vitro biochemical analysis of the co-chaperone function of three E. coii Hsp40s proteins (DnaJ, CbpA and DjlA) in the ATP-fuelled DnaK-mediated refolding of a model DnaK chaperone substrate into its native state. Hsp40s activities were compared using dose-response approaches in two types of in vitro assays: refolding of heat-denatured G6PDH and DnaK-mediated ATPase activity. We also observed that the disaggregation efficiency of Hsp70 does not directly correlate with Hsp40 binding affinity. Besides, we found that these E. coii Hsp40s confer substrate specificity to DnaK, CbpA being more effective in the DnaK-mediated disaggregation of large G6PDH aggregates than DnaJ under certain conditions. Sensibilisées par différents stress ou mutations, certaines protéines fonctionnelles de la cellule peuvent spontanément se convertir en formes inactives, mal pliées, enrichies en feuillets bêta, et exposant des surfaces hydrophobes favorisant l'agrégation. Cherchant à se stabiliser, les surfaces hydrophobes peuvent s'associer aux régions hydrophobes d'autres protéines mal pliées, formant des agrégats protéiques stables: les amyloïdes. Le dépôt intracellulaire de protéines agrégées est un dénominateur commun à de nombreuses maladies neurodégénératives. Afin de contrer la cytotoxicité induite par les protéines agrégées, les cellules ont développé plusieurs mécanismes de défense, parmi lesquels, les chaperonnes moléculaires Hsp70. Hsp70 nécessite la collaboration de deux autres co-chaperonnes : Hsp40 et NEF pour accomplir son activité de désagrégation. Hsp70 (DnaK, chez E. coli) est impliquée par ailleurs dans d'autres fonctions physiologiques telles que l'assistanat de protéines néosynthétisées à la sortie du ribosome, ou le transport transmembranaire de polypeptides. Par ailleurs, les chaperonnes Hsp70 peuvent également solubiliser et réactiver des protéines agrégées à la suite d'un stress ou d'une mutation. Dans la première partie expérimentale de cette thèse (Chapter II), nous avons étudié in vitro l'interaction entre les oligomères d'a-synucleine, responsables entre autres, de la maladie de Parkinson, et le système chaperon Hsp70/Hsp40 (système Escherichia coli DnaK/DnaJ/GrpE). Nous avons démontré que contrairement aux monomères, les oligomères d'a-synucleine inhibaient le système chaperon lors du repliement de protéines agrégées. Cette dysfonction du système chaperon résulte de la séquestration des chaperonnes Hsp40 par les oligomères d'a-synucleine. La deuxième partie expérimentale (Chapitre III) est consacrée à une étude in vitro de la fonction co-chaperonne de trois Hsp40 d'is. coli (DnaJ, CbpA, et DjlA) lors de la désagrégation par DnaK d'une protéine pré-agrégée. Leurs activités ont été comparées par le biais d'une approche dose-réponse au niveau de deux analyses enzymatiques: le repliement de la protéine agrégée et l'activité ATPase de DnaK. Par ailleurs, nous avons mis en évidence que l'efficacité de désagrégation d'Hsp70 et l'affinité des chaperonnes Hsp40 vis-à-vis de leur substrat n'étaient pas corrélées positivement. Nous avons également montré que ces trois chaperonnes Hsp40 étaient directement impliquées dans la spécificité des fonctions accomplies par les chaperonnes Hsp70. En effet, DnaK en présence de CbpA assure la désagrégation de large agrégats protéiques avec une efficacité nettement plus accrue qu'en présence de DnaJ.

[Voyage en Italie : 1824-1830]. , Chiesa di S. Giacomo : [vues perspectives de la façade et de la nef] : [dessin] / h. L. [Henri Labrouste]

Référence bibliographique : Weigert, 37

[Voyage en Italie : 1824-1830]. , [Vue du plafond] à S. Michele in Bosco : [plan partiel de la nef et du chœur, relevé des décors du plafond à caissons] : [dessin] / h. L. [Henri Labrouste]

Référence bibliographique : Weigert, 46

[Voyage en Italie : 1824-1830]. , Bains de Cicéron à Mola di Gaeta (Formie) : [plan, vue perspective de la nef] : [dessin] / h. L. [Henri Labrouste]

Référence bibliographique : Weigert, 172