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Davide Corti,
Jarrod Voss,
Steven J Gamblin,
Giosiana Codoni,
Annalisa Macagno,
David Jarrossay,
Sebastien G Vachieri, Debora Pinna,
Andrea Minola,
Fabrizia Vanzetta, [......],
Siro Bianchi,
Isabella Giacchetto-Sasselli,
Lesley Calder,
Federica Sallusto,
Patrick Collins,
Lesley F Haire,
Nigel Temperton,
Johannes P M Langedijk,
John J Skehel,
Antonio Lanzavecchia
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ABSTRACT: The isolation of broadly neutralizing antibodies against influenza A viruses has been a long-sought goal for therapeutic approaches and vaccine design. Using a single-cell culture method for screening large numbers of human plasma cells, we isolated a neutralizing monoclonal antibody that recognized the hemagglutinin (HA) glycoprotein of all 16 subtypes and neutralized both group 1 and group 2 influenza A viruses. Passive transfer of this antibody conferred protection to mice and ferrets. Complexes with HAs from the group 1 H1 and the group 2 H3 subtypes analyzed by x-ray crystallography showed that the antibody bound to a conserved epitope in the F subdomain. This antibody may be used for passive protection and to inform vaccine design because of its broad specificity and neutralization potency.
Science 08/2011; 333(6044):850-6. · 31.20 Impact Factor
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Davide Corti,
Amorsolo L Suguitan, Debora Pinna,
Chiara Silacci,
Blanca M Fernandez-Rodriguez,
Fabrizia Vanzetta,
Celia Santos,
Catherine J Luke,
Fernando J Torres-Velez,
Nigel J Temperton,
Robin A Weiss,
Federica Sallusto,
Kanta Subbarao,
Antonio Lanzavecchia
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ABSTRACT: The target of neutralizing antibodies that protect against influenza virus infection is the viral protein HA. Genetic and antigenic variation in HA has been used to classify influenza viruses into subtypes (H1-H16). The neutralizing antibody response to influenza virus is thought to be specific for a few antigenically related isolates within a given subtype. However, while heterosubtypic antibodies capable of neutralizing multiple influenza virus subtypes have been recently isolated from phage display libraries, it is not known whether such antibodies are produced in the course of an immune response to influenza virus infection or vaccine. Here we report that, following vaccination with seasonal influenza vaccine containing H1 and H3 influenza virus subtypes, some individuals produce antibodies that cross-react with H5 HA. By immortalizing IgG-expressing B cells from 4 individuals, we isolated 20 heterosubtypic mAbs that bound and neutralized viruses belonging to several HA subtypes (H1, H2, H5, H6, and H9), including the pandemic A/California/07/09 H1N1 isolate. The mAbs used different VH genes and carried a high frequency of somatic mutations. With the exception of a mAb that bound to the HA globular head, all heterosubtypic mAbs bound to acid-sensitive epitopes in the HA stem region. Four mAbs were evaluated in vivo and protected mice from challenge with influenza viruses representative of different subtypes. These findings reveal that seasonal influenza vaccination can induce polyclonal heterosubtypic neutralizing antibodies that cross-react with the swine-origin pandemic H1N1 influenza virus and with the highly pathogenic H5N1 virus.
The Journal of clinical investigation 04/2010; 120(5):1663-73. · 15.39 Impact Factor
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Davide Corti,
Johannes P M Langedijk,
Andreas Hinz,
Michael S Seaman,
Fabrizia Vanzetta,
Blanca M Fernandez-Rodriguez,
Chiara Silacci, Debora Pinna,
David Jarrossay,
Sunita Balla-Jhagjhoorsingh, [......],
Simon A Jeffs,
David C Montefiori,
David Davis,
Winfried Weissenhorn,
Aine McKnight,
Jonathan L Heeney,
Federica Sallusto,
Quentin J Sattentau,
Robin A Weiss,
Antonio Lanzavecchia
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ABSTRACT: The isolation of human monoclonal antibodies (mAbs) that neutralize a broad spectrum of primary HIV-1 isolates and the characterization of the human neutralizing antibody B cell response to HIV-1 infection are important goals that are central to the design of an effective antibody-based vaccine.
We immortalized IgG(+) memory B cells from individuals infected with diverse clades of HIV-1 and selected on the basis of plasma neutralization profiles that were cross-clade and relatively potent. Culture supernatants were screened using various recombinant forms of the envelope glycoproteins (Env) in multiple parallel assays. We isolated 58 mAbs that were mapped to different Env surfaces, most of which showed neutralizing activity. One mAb in particular (HJ16) specific for a novel epitope proximal to the CD4 binding site on gp120 selectively neutralized a multi-clade panel of Tier-2 HIV-1 pseudoviruses, and demonstrated reactivity that was comparable in breadth, but distinct in neutralization specificity, to that of the other CD4 binding site-specific neutralizing mAb b12. A second mAb (HGN194) bound a conserved epitope in the V3 crown and neutralized all Tier-1 and a proportion of Tier-2 pseudoviruses tested, irrespective of clade. A third mAb (HK20) with broad neutralizing activity, particularly as a Fab fragment, recognized a highly conserved epitope in the HR-1 region of gp41, but showed striking assay-dependent selectivity in its activity.
This study reveals that by using appropriate screening methods, a large proportion of memory B cells can be isolated that produce mAbs with HIV-1 neutralizing activity. Three of these mAbs show unusual breadth of neutralization and therefore add to the current panel of HIV-1 neutralizing antibodies with potential for passive protection and template-based vaccine design.
PLoS ONE 01/2010; 5(1):e8805. · 4.09 Impact Factor
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ABSTRACT: The analysis of the human memory B-cell repertoire is of both fundamental and practical significance. We developed a simple method for the selective activation of memory B cells in total fresh or frozen PBMC using a combination of R848 and IL-2. In these conditions, 30-40% of memory B cells generated clones producing on average 200 ng IgG in 10 days. This method was used to measure the frequency of antigen-specific memory B cells as well as the fine specificity, cross-reactivity and neutralizing activity of the secreted antibodies. Following influenza vaccination, specific B cells expanded dramatically, reaching up to 50% of total clonable memory B cells on day 14. Specific B-cell expansions were detected also in individuals that did not show a significant serological response. Dynamic changes and persistence of B cells specific for a variety of pathogens were documented in serial PBMC samples collected over almost two decades. These results reveal novel aspects of memory B-cell kinetics and provide a powerful tool to monitor immune responses following infection and vaccination.
European Journal of Immunology 05/2009; 39(5):1260-70. · 5.10 Impact Factor
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Debora Pinna,
Pasqua Oreste,
Tiziana Coradin,
Anna Kajaste-Rudnitski,
Silvia Ghezzi,
Giorgio Zoppetti,
Antonella Rotola,
Rafaela Argnani,
Guido Poli,
Roberto Manservigi,
Elisa Vicenzi
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ABSTRACT: Herpes simplex virus type 1 (HSV-1) and HSV-2 are neurotropic viruses and common human pathogens causing major public health problems such as genital herpes, a sexually transmitted disease also correlated with increased transmission and replication of human immunodeficiency virus type 1 (HIV-1). Therefore, compounds capable of blocking HIV-1, HSV-1, and HSV-2 transmission represent candidate microbicides with a potential added value over that of molecules acting selectively against either infection. We report here that sulfated derivatives of the Escherichia coli K5 polysaccharide, structurally highly similar to heparin and previously shown to inhibit HIV-1 entry and replication in vitro, also exert suppressive activities against both HSV-1 and HSV-2 infections. In particular, the N,O-sulfated [K5-N,OS(H)] and O-sulfated epimerized [Epi-K5-OS(H)] forms inhibited the infection of Vero cells by HSV-1 and -2, with 50% inhibitory concentrations (IC(50)) between 3 +/- 0.05 and 48 +/- 27 nM, and were not toxic to the cells at concentrations as high as 5 muM. These compounds impaired the early steps of HSV-1 and HSV-2 virion attachment and entry into host cells and reduced the cell-to-cell spread of HSV-2. Since K5-N,OS(H) and Epi-K5-OS(H) also inhibit HIV-1 infection, they may represent valid candidates for development as topical microbicides preventing sexual transmission of HIV-1, HSV-1, and HSV-2.
Antimicrobial Agents and Chemotherapy 07/2008; 52(9):3078-84. · 4.84 Impact Factor
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ABSTRACT: There is currently an urgent need to identify effective antiviral agents that will prevent and treat severe acute respiratory syndrome coronavirus (SARS-CoV) infection. In this study, we have investigated and compared the antiviral effect of different interferons (IFNs) on SARS-CoV replication in the epithelial kidney monkey Vero cell line. The results showed that SARS-CoV grown in Vero cells is moderately sensitive to IFN-beta and only weakly sensitive to IFN-alpha and IFN-gamma, in comparison to other IFN-sensitive viruses, such as those for encephalomyocarditis, vesicular stomatitis and Newcastle disease. Simultaneous incubation of Vero cells with IFN-beta and IFN-gamma indicated that they may act synergistically against SARS-CoV replication. The IFN-induced MxA protein was detected in the IFN-treated Vero cells. The data, however, suggest that the antiviral activity of IFN against SARS-CoV virus is independent of MxA expression.
Antiviral therapy 01/2005; 9(6):1003-11. · 3.16 Impact Factor
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ABSTRACT: During the recent severe acute respiratory (SARS) outbreak, the etiologic agent was identified as a new coronavirus (CoV). We have isolated a SARS-associated CoV (SARS-CoV) strain by injecting Vero cells with a sputum specimen from an Italian patient affected by a severe pneumonia; the patient traveled from Vietnam to Italy in March 2003. Ultrastructural analysis of infected Vero cells showed the virions within cell vesicles and around the cell membrane. The full-length viral genome sequence was similar to those derived from the Hong-Kong Hotel M isolate. By using both real-time reverse transcription-polymerase chain reaction TaqMan assay and an infectivity plaque assay, we determined that approximately 360 viral genomes were required to generate a PFU. In addition, heparin (100 microg/mL) inhibited infection of Vero cells by 50%. Overall, the molecular and biologic characteristics of the strain HSR1 provide evidence that SARS-CoV forms a fourth genetic coronavirus group with distinct genomic and biologic features.
Emerging infectious diseases 04/2004; 10(3):413-8. · 6.17 Impact Factor
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ABSTRACT: Two different prime-boost immunization protocols were tested in rabbits and their immune response was evaluated and compared with the final aim of defining a vaccine strategy that might be able to protect non-human primates from infection with the pathogenic simian/human immunodeficiency virus, SHIV(89.6P). The two regimens were based on three priming immunizations with either an expression plasmid plus a fowlpox (FP) recombinant vector or with two FP recombinant vectors, each one expressing either the SIV(mac239) gag/pol or the HIV-1env(89.6P) genes. In both protocols, priming immunizations were followed by two boosts with SHIV-mimicking virus-like particles (VLP). A complete SHIV-specific response was observed in all animals. Interestingly, the DNA vaccine was three to 10 times more efficient than the FP recombinant in inducing an anti-gag humoral response. Real-time PCR confirmed the memory effect on T-cell subsets secreting interleukin-4 and interferon-gamma, as a consequence of stimulation of both arms of the immune system. Although both protocols were almost equally effective in eliciting homologous neutralizing antibodies and highlighted the efficacy of VLP administration for boosting, protocol A seemed to be more effective in promoting a balanced T-cell memory immune response and appears more promising for vaccine purposes.
FEMS Immunology & Medical Microbiology 02/2003; 35(1):59-65. · 2.44 Impact Factor
