O habitat natural da Neisseria meningitis é a nasofaringe humana e a transmissão da bactéria é por contato direto ou por inalação de partículas durante a fase de transmissão N. meningitis é uma bactéria Gram-negativa responsável por uma significante mortalidade em todo o mundo. Embora existam vacinas polissacárides contras os sorogrupos A, C, W135 e Y , não há uma vacina adequada para crianças menores de 4 anos para o sorogrupo B. Estudos estão sendo direcionadas para pesquisa de antígenos vacinais que são derivados da proteínas de membrana externa(NOMV). Entretanto vacinas baseadas em NOMV são consideradas pouco imunogênicas , fazendo com que o uso de adjuvantes seja necessário. Este estudo investiga a imunogenicidade da NOMV de N. meningitidis administrada pela via intranasal/intramuscular em camundongos neonatos BALC/c, usando proteína de membrana externa (NOMC) obtido de uma cepa epidêmica de N. meningitidis B:4:P1:15. As cepas usadas para imunização dos camundongos foram selecionadas por colony-blot, usando anticorpo monoclonal anti L3,7,9 para maior expressão do LPS contra o imunotipo L3,7,9 presente na cepa (B:4:P1:15 3,7,9). Como adjuvantes de mucosa foram utilizados Bordetella pertussis (células íntegras) ou sobrenadante de cultura com 48 horas ou hidróxido de alumínio [Al(OH)3]. O soro dos camundongos imunizados foram analisados pelo método de ELISA à fim de se comparar os diferentes adjuvantes utilisados. O índice de avidez também foi determinado. IgG e IgM foram detectados nos soros dos camundongos após imunização, com índices de intermediária e alta avidez. Todos os adjuvantes foram capazes de aumentar a resposta imune contra NOMV de N.meningitidis. A via intranasal foi adequada para sensibilizar as células do sistema imune que foram rapidamente estimuladas pela via intramuscular usando os adjuvantes utilizados na presente investigação. Dados sugerem que o estudo da NOMV é importante na indução da imunidade de mucosa para N. meningitidis B, e que a qualidade e magnitude da resposta imune gerada pelas vacinas de mucosa são influenciadas tanto pelo adjuvante como pelo antígeno. Concluímos que NOMV juntamente com adjuvantes de mucosa tem considerável potencial no desenvolvimento de vacinas contra o meningococo do sorogrupo B. / The natural habitat of Neisseria meningitidis is the human nasopharynx, and the bacterium is transmitted by direct mouth-to-mouth contact or by the inhalation of released mucous particles during close contact. N meningitidis is a Gram-negative bacterium responsible for significant mortality worldwide. While effective polysaccharide-based vaccines exist against serogroups A, C, W135, and Y, no similar vaccine is suitable for children under 4 years against disease caused by serogroup B strains. Current studies are searching for vaccinal antigens that are derived from the native outer membrane (NOMV). However, vaccines based on NOMV are considered weak, making the use of adjuvants necessary. This study investigated the immunogenicity of NOMV of N. meningitidis administered intranasal/intramuscular in neonate BALB/c mice, using the native outer membrane complex (NOMC) obtained from an epidemic strain of N. meningitidis B:4:P1.15. The strains used for immunization of mice were selected by colony-blot, using anti L3,7,9 monoclonal antibodies, for the highest expression of LPS among the immunotypes (B:4:P1:15 L9á). As mucosal adjuvants, we used Bordetella pertussis (whole cells) or the supernatant of 48 h culture of this bacterium, followed by an intramuscular dose of the same protein adsorbed onto , B. pertussis (whole cells) or 48-h B. pertussis culture supernatant or aluminum hydroxide [Al(OH)3]. Sera of immunized mice were evaluated by ELISA in order to compare the different adjuvants used. We also determined their avidity index. IgG and IgM were detected in the serum of mice after immunization, with avidity indices that ranged from intermediate to high. All adjuvants were capable of increasing the immune response against NOMV of N. meningitidis in the homologous prime/boost schedule used. The intranasal route was suitable for sensitizing the cells of the immune system which were quickly stimulated by the intramuscular route using the adjuvants analysed in the present invertigation. Data suggest that the NOMV studied is important in the induction of mucosal immunity to N. meningitidis B, and that the quality and magnitude of the immune responses generated by mucosal vaccines are influenced by the adjuvant as well as the antigen. In conclusion, nasal delivery of NoMV with mucosal adjuvants has considerable potential in the development of a mucosal vaccine against serogroup B meningococci.

Bordetella pertussis is the causative agent of whooping cough which is a worldwide acute respiratory disease that predominantly involves infants. Whooping cough is one of the ten most common causes of death from infectious diseases worldwide. The increased coverage of the primary pertussis vaccination (DaBT-IPA-Hib) decreased the incidence of disease in Turkey dramatically. However, in spite of the incidence decline, the circulation of B. pertussis has not yet been eliminated, and a change in the clinical spectrum and age-related incidence of the disease has been observed. On the other hand, in view of the moderate changes that have been observed in the genomic sequences of certain virulance factors over time, there are concerns about the gradual loss of the efficacy of the current pertussis vaccines as a result of antigenic drift and continuous selection of the least vaccine-sensitive clones. Proteomics deals with whole protein content (proteome) of cells as a function of space and time. Gel-based approach in proteomics involves two dimensional gel electrophoresis (2-DE) followed by peptide mass fingerprinting (PMF) employing matrix-assisted laser desorption/ionization (MALDI)-mass spectrometry (MS). Immunoproteomics which is a combination of gel based proteomics and Western blot analysis determines tumor-specific antigens as well as immunoreactive proteins of pathogens by combining proteomics with Western blot technique. Although immunoproteomics is a rather new research tool, it has been quite effective to determine the virulence factors of various pathogenic microorganisms. The present study aims at comparing immunoproteome of the standard B. pertussis strain &ldquo / Tahoma I&rdquo / with those of two other strains, namely &ldquo / Saadet&rdquo / and &ldquo / Nursel&rdquo / , which are the local isolates that have been preferred as the vaccine strains for many years in our country for their ability to provide a better protection. Of a total of 38 immunogenic proteins identified, 14 were shown to be the novel antigens for B. pertussis. Among 14 proteins, one was detected as immunogenic in only Tohama I strain where two proteins were specific for Nursel strain. Among the strains compared, Saadet strain had the highest antigenic variety, than the others.

Whooping cough (pertussis) is a highly contagious respiratory infection caused by Bordetella pertussis. It becomes widespread among adolescent and adults as well as infants. Although availability of effective pertussis vaccines seems to decrease the incidence of the disease, B. pertussis circulation in population has not been eliminated. It is thought that the antigenic drifts in major protective antigens and continued circulation of B. pertussis strains will result in gradual loss of the efficacy of the current pertussis vaccines. Therefore, development of more effective acellular pertussis vaccines with conserved protective proteins is a convenient strategy to provide a better protection against whooping cough. In this study, immune responses against putative peptidyl-prolyl cis-trans isomerase (PPIase) which was shown to be immunogenic in B. pertussis for the first time by our immunoproteome group and FimX whose expression was found higher in our local Saadet strain were determined in mice. The genes encoding FimX and putative PPIase were amplified by PCR, cloned into pGEM&reg / -T Easy vector and sequenced. The genes were then introduced into pET-28a (+) vector and they were expressed in Escherichia coli BL21(DE3) cells. The recombinant proteins were purified by His-tag affinity chromatography and dialyzed. After Western blot analyses, 20 &micro / g and 80 &micro / g recombinant FimX and 80 &micro / g recombinant putative PPIase were used to immunize BALB/c mice (16-18 g) at day 0 and 21. The mice were challenged intranasally with 2.5 x 109 live B. pertussis Saadet cells. Before second immunization and challenge, the sera were collected to carry out ELISA for measurement of serum-specific IgG levels. According to ELISA results, IgG levels in the mice immunized with 20 &micro / g and 80 &micro / g recombinant FimX were found significantly higher than in control groups at both first and second vaccinations (p&lt / 0.01). On the other hand, immunization with 160 &micro / g recombinant putative PPIase provided a significant increase in IgG level (p&lt / 0.05) only at second vaccination. The lungs of the mice were removed at day 2, 5, 8 after challenge and bacterial colonization was determined. No significant decrease in bacterial colonization was observed in the lungs of the mice immunized with 20 &micro / g and 80 &micro / g recombinant FimX and 80 &micro / g recombinant putative PPIase with respect to control groups. After respiratory challenge and second immunization (at day 30) with 20 &micro / g and 80 &micro / g recombinant FimX, the spleens of the mice were removed and a spleen cell culture was obtained. Supernatants were collected after induction of the cells with the recombinant protein and cytokine ELISA was carried out to measure IFN-&gamma / level. No significant difference was observed between control and vaccinated mice in terms of IFN-&gamma / production.

Bordetella pertussis is a gram-negative, human pathogen and etiologic agent of whooping cough (pertussis), a highly contagious, acute respiratory illness. In this study, the analysis of whole immunproteome and subproteomes of this microorganism was performed. The soluble cytoplasmic proteomes of B. pertussis Tohama I strain and a local isolate Saadet were separated by 2DE. By Western blot analysis, we identified 25 immunogenic proteins of three categories. In the first group, there were well-known proteins of the pathogen The second group comprised proteins which were already shown antigenic in certain pathogenic bacteria, but not in B. pertussis before. The third group of proteins were those which have not been shown to be immunogenic in any pathogen till the present study such as putative chromosome partition protein, preprotein translocase SecA subunit, carbamoyl-phosphate synthase large chain, PRP synthase, putative substrate-CoA ligase, lysyl-tRNA synthetase, fumaryl acetoacetase, putative peptidyl-prolyl cis-trans isomerase, aspartate-semialdehyde dehydrogenase, putative DNA-binding protein and a putative outer membrane protein. In our surfaceome study, surface proteins of two strains were identified by 2DE followed by MALDI-TOF-MS/MS analysis and also geLC-MS/MS. With these techniques 45 proteins were identified by 2DE and 226 proteins by geLC-MS/MS. The immunogenicity of surface proteins on 2DE gels were analyzed by Western blotting and among 11 identified immunogenic proteins glutamine-binding periplasmic protein, leu/ile/val-binding protein, one putative exported protein, and iron-superoxide dismutase were found to be immunogenic for the first time in Bordetella. It was also found that 16 proteins were differentially expressed in B. pertussis Saadet and Tohama I. Five proteins were expressed only in Saadet (adhesin, chaperone protein DnaJ, fimbrial protein FimX, putative secreted protein Bsp22 and putative universal stress protein), and two (ABC transporter substrate-binding protein and a putative binding protein-dependent transport periplasmic protein) only in Tohama I. In the secretome study, we identified 40 proteins by 2DE and 357 proteins by geLC-MS/MS. It was found that 12 proteins were immunogenic by Western blot analysis and the immunogenicity of putative secreted protein (BP1047) was shown for the first time in this study. In our study, PT subunit 2 and putative outer protein D (BopD) were more abundant in Saadet while one protein, glutamate synthase subunit beta was expressed at a higher level in Tohama I. Four proteins were expressed only in Saadet (two capsular polysaccharide biosynthesis protein, protein FimX and putative outer membrane permeability protein). The present study comprehensively covered almost the entire proteome of a crucial pathogen, demonstrated many novel antigens and identified hundreds of membrane-bound proteins, cell surface-associated and extracellular proteins. Thus, it is anticipated to greatly aid in a better understanding of pathogen-host relations, rational design of novel drugs and developing new generation vaccines against B. pertussis.

Thèse de doctorat : Sciences de la vie et de la santé : Lille 1 : 2001. / Résumé en français et en anglais. Textes en français et en anglais. Bibliogr. f. 232-270. Notes bibliogr.

Disease caused by Bordetella pertussis persists with rates increasing over the past decade in industrialized countries. A hindrance to vaccine development has been the lack of a clear serological correlate of protective immunity. Pertussis toxin (PTx), an AB-type toxin, is one of the bacteria’s major virulence factors and among the lead candidates for potential correlates. Of the numerous monoclonal antibodies (mAbs) binding PTx, the murine IgG2a mAb 1B7 is potently neutralizing in all in vitro assays and in vivo murine models of infection. 1B7 binds an epitope on the enzymatic S1-subunit of PTx with some linear elements but previous work was unable to more precisely define the epitope or determine its exact mechanism of protection. We characterize the epitope bound by 1B7 on PTx-S1 in molecular detail and define energetically important interactions between residues at the interface including six residues on PTx-S1 and six residues on 1B7. Using this information, a model of the 1B7-S1 interaction was developed, indicating a predominantly conformational epitope located on the base of S1 near S4. The location of this epitope is consistent with previous data and is shown to be conserved across several naturally occurring strain variants including PTx-S1A, B, D, and E in addition to the catalytically inactive 9K/129G variant. Using immunofluorescent microscopy, it was determined that 1B7’s unique mode of action lies in its ability to bind to the toxin and co-traffic into target cells. Upon endocytosis, 1B7 protects from PTx intoxication by redirecting its intracellular retrograde trafficking. In order to determine whether antibody responses are differently induced by infection or acellular vaccination, we analyzed sera from 30 adults with confirmed exposure to pertussis and 30 recent vaccinees. Natural infection resulted in significantly higher titers of anti-PTx-S1, 1B7-like, and 11E6-like antibodies, while overall anti-PTx titers were similar to vaccinated samples. We also observed a direct correlation between in vitro protection and the presence of 1B7-like and 11E6-like antibodies. Thus, natural infection elicits higher titers of protective antibodies indicating that the use of detoxified PTx in current acellular vaccines although highly immunogenic results in the elicitation of predominantly non-neutralizing antibodies. / text

El aumento creciente de la incidencia de Bordetella pertussis en poblaciones con elevada cobertura de vacunación ha puesto de manifiesto que las vacunas en uso presentan falencias que han cobrado importancia con el tiempo. Con el fin diseñar vacunas con mayor capacidad protectora nuestra investigación se ha orientado al estudio del fenotipo infectante. Parte de los esfuerzos en este sentido se han centrado en la identificación de los cambios fenotípicos inducidos en B. pertussis en respuesta a la falta de hierro libre, por ser éste el stress nutricional mas importante durante infección. Para ello se ha elegido una estrategia de trabajo que es una combinación de proteómica bidimensional comparativa y análisis serológico del proteoma. La ventaja de emplear esta estrategia es que permitió identificar potenciales factores de virulencia y, a la vez, seleccionar inmunógenos que se expresan en condiciones fisiológicas y que, sin embargo, no están incluidos en ninguna de las formulaciones vacunales en uso. En este trabajo de tesis, por un lado se amplió la caracterización del proteoma de B. pertussis cultivada bajo limitación de hierro mediante una proteómica shotgun, una técnica que presenta alta sensibilidad. Además se describen dos nuevos inmunógenos capaces de mejorar la protección conferida por la vacuna acelular actualmente en uso.

El objetivo general de esta tesis es generar conocimiento sobre los aspectos claves de la respuesta inicial frente a una infección respiratoria para aplicarlo en la formulación de estrategias de inmunoprofilaxis de la enfermedad. Este trabajo puede servir de prueba de concepto para contrastar las hipótesis enunciadas. Con este fin, emplearemos el modelo murino de infección por B. pertussis, analizando la contribución de distintos receptores TLR en la inducción de la defensa mucosal frente a la infección para luego evaluar cómo la activación de dichas vías en protocolos de inmunización intranasal son capaces de dar origen a respuestas protectivas frente al desafío intranasal con B. pertussis.

Mestre -- Instituto Nacional de Controle de Qualidade em Saude, Rio de Janeiro, 2003.

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