L’entérotoxine B staphylococcique (SEB) est une toxine entérique hautement résistante à la chaleur et est responsable de plus de 50 % des cas d’intoxication d’origine alimentaire par une entérotoxine. L’objectif principal de ce projet de maîtrise est de développer et valider une méthode basée sur des nouvelles stratégies analytiques permettant la détection et la quantification de SEB dans les matrices alimentaires. Une carte de peptides tryptiques a été produite et 3 peptides tryptiques spécifiques ont été sélectionnés pour servir de peptides témoins à partir des 9 fragments protéolytiques identifiés (couverture de 35 % de la séquence). L’anhydride acétique et la forme deutérée furent utilisés afin de synthétiser des peptides standards marqués avec un isotope léger et lourd. La combinaison de mélanges des deux isotopes à des concentrations molaires différentes fut utilisée afin d’établir la linéarité et les résultats ont démontré que les mesures faites par dilution isotopique combinée au CL-SM/SM respectaient les critères généralement reconnus d’épreuves biologiques avec des valeurs de pente près de 1, des valeurs de R2 supérieure à 0,98 et des coefficients de variation (CV%) inférieurs à 8 %. La précision et l’exactitude de la méthode ont été évaluées à l’aide d’échantillons d’homogénat de viande de poulet dans lesquels SEB a été introduite. SEB a été enrichie à 0,2, 1 et 2 pmol/g. Les résultats analytiques révèlent que la méthode procure une plage d’exactitude de 84,9 à 91,1 %. Dans l’ensemble, les résultats présentés dans ce mémoire démontrent que les méthodes protéomiques peuvent être utilisées efficacement pour détecter et quantifier SEB dans les matrices alimentaires. Mots clés : spectrométrie de masse; marquage isotopique; protéomique quantitative; entérotoxines / Staphylococcal enterotoxin B is a highly heat-resistant enteric toxin and it is responsible for over 50% of enterotoxin food poisoning. It represents a particular challenge during food processing since, even if the bacteria have been destroyed, the biological activity of the toxin remains unchanged. The objective of this study was to develop and validate a new method based on a novel proteomic strategy to detect and quantify SEB in food matrices. Tryptic peptide map was generated and 3 specific tryptic peptides were selected and used as surrogate peptides from 9 identified proteolytic fragments (sequence coverage of 35%). Peptides were label with light and heavy form of acetic anhydride to create an isobaric tag that will allow quantification. The linearity was tested using mixtures of different molar ratios and the results showed that measurements by LC-MS/MS were within generally accepted criteria for bioassays with slope values near to 1, values of R2 above 0.98 and less than 8% coefficient of variation (%CV). The precision and accuracy of the method were assessed using chicken meat homogenate samples spiked with SEB at 0.2, 1 and 2 pmol/g. The results indicated that the method can provide accuracy within 84.9 – 91.1% range. Overall, the results presented in this thesis show that proteomics-based methods can be effectively used to detect, confirm and quantify SEB in food matrices. Keywords: mass spectrometry; stable isotope labeling; quantitative proteomics; enterotoxins

INTRODUÇÃO: A dermatite atópica (DA) é uma doença cutânea inflamatória, acompanhada por prurido intenso e xerose cutânea. A etiopatogenia da DA é multifatorial, envolvendo fatores genéticos, ambientais e imunológicos, dentre outros. OBJETIVOS: Avaliar a influência das enterotoxinas A e B do Staphylococcus aureus (SEA e SEB) na resposta mediada por células Th17 e Th22 nos indivíduos adultos com DA. MÉTODOS: Foram selecionados 38 pacientes adultos com DA e um grupo controle com 40 indivíduos adultos, pareados por idade e gênero Os métodos utilizados foram: 1) ELISA: dosagem dos níveis séricos de IL-6, IL-17, IL-22 e IL-12p40/IL-23 e em sobrenadantes de culturas de células mononucleares do sangue periférico (PBMC) estimuladas com SEA e SEB; 2) Imuno-histoquímica: análise da expressão de IL-17 em fragmentos de pele; 3) Citometria de fluxo: a) análise das citocinas circulantes em amostras de soro: IL-2, IL-4, IL-5, IL-6, IL-10, TNF, IL-17A e IFN-y b)avaliação das células T CD4+ mono e polifuncionais secretoras de IL-17, IL-22, TNF, IFN-y, MIP-1beta, e expressão do marcador de ativação celular CD38; c) células Th22 e Tc22 estimuladas com SEA e SEB. RESULTADOS: 1) Através do ELISA, a secreção de IL-22 sérica e em PBMC induzidas por SEA e SEB foi significativamente mais elevada, quando comparada ao grupo controle; 2) houve aumento na expressão de IL-17 em amostras de pele de doentes de DA através da imuno-histoquímica; 3) Através da citometria de fluxo, foram detectados: a) níveis séricos de IL-2, 5, 6, 10, 17A e IFN-y elevados no grupo com DA em relação aos controles; houve diferença significativa nos níveis circulantes de IL-17A nos pacientes com DA moderada e grave; b) na avaliação monofuncional das células T CD4+ sob estímulo de SEA/SEB, houve redução da expressão das citocinas IFN-y, IL-17A, IL-22 ou TNF na DA, quando comparadas ao grupo controle; na análise polifuncional das células T CD4+/CD8+, ocorreu redução da resposta na DA em relação aos controles; nos pacientes atópicos encontramos aumento da resposta em situação basal na dependência de CD38, e redução na resposta frente a SEA/SEB na ausência de CD38; c) encontramos resposta reduzida das células Th22, e elevada de células Tc22 frente aos estímulos SEA e SEB, nos pacientes com DA. CONCLUSÕES: O estudo corrobora o papel patogênico das enterotoxinas estafilocócicas na DA. A ativação crônica com superantígenos estafilocócicos pode contribuir com a alta frequência de células T CD4+ CD38+ polifuncionais, e com a resposta polifuncional anérgica, mediadas por células T CD38- / BACKGROUND: Atopic dermatitis (AD) is an inflammatory skin disease with intense itching and xerosis. AD pathogenesis is multifactorial, involving genetic, environmental, and immunological factors, among others. OBJECTIVES: To evaluate the influence of enterotoxins A and B from Staphylococcus aureus (SEA and SEB) in Th17 and Th22 cell response in adults with AD. METHODS: We evaluated 38 adult patients with AD, and a control group of 40 adults, age and gender matched. Assays: 1) ELISA: evaluation of IL-6, IL-17, IL-12p40/IL-23 and IL-22 serum levels and in supernatants of mononuclear cell cultures from peripheral blood (PBMC), stimulated with SEA/SEB; 2) Immunohistochemistry: analysis of IL-17 expression in skin specimens; 3) Flow cytometry: a) analysis of circulating cytokines in serum samples: IL-2, IL-4, IL-5, IL-6, IL-10, TNF, IL-17A and IFN-y b) evaluation of mono and polyfunctional TCD4+ cells that secrete IL-17, IL-22, TNF, IFN-y, MIP-1beta, and expression of the activation marker CD38; c) analysis of Tc22 and Th22 cells stimulated with SEA and SEB. RESULTS: 1) Secretion of IL-22 in the serum and from supernatants of cell cultures from PBMC, stimulated with SEA and SEB were higher in AD patients, when compared to the control group by ELISA; 2) there was an increase of IL-17 expression in skin samples by immunohistochemistry; 3) Flow cytometry showed: a) elevated serum levels of IL-2, 5, 6, 10, 17A and IFN-y in AD, when compared to controls; there was a significant difference in circulating levels of IL-17A in patients with moderate and severe disease; b) monofunctional evaluation of T CD4+ cells under SEA/SEB stimuli showed reduced expression of IFN-y, IL-17A, IL-22 or TNF cytokines in AD, compared to controls; the same was observed for polyfunctional CD4+/CD8+ T cells analysis, exhibiting a diminished response in AD. In atopic patients under basal conditions, there was an augmented CD38- dependent response and reduced pattern to SEA/SEB in the absence of CD38; c) finally, we observed a reduced response of Th22 cells and enhanced Tc22 cells under SEA/SEB stimuli in patients with AD. CONCLUSIONS: This study corroborates the pathogenic role of staphylococcal enterotoxins in AD. Chronic activation with staphylococcal superantigens may contribute to the high frequency of polyfunctional CD4 +CD38+ T cells and with the anergic polyfunctional response mediated by T CD38- T cells

Les staphylocoques à coagulase négative (SCN) sont généralement considérés comme des pathogènes opportunistes à faible virulence. Cependant, des études antérieures ont rapporté une pathogénicité de certaines souches similaire à celle observée chez S. aureus ce qui laisse supposer l’expression de facteurs de virulence. Cette thèse vise à contribuer à l’importance des SCN dans les infections primitives sévères. Nous avons évalué le potentiel pathogène de souches cliniques de SCN au Bénin. Pour atteindre cet objectif, des SCN associés à diverses infections cliniques sévères ont été collectés sur une période de 10 mois au Centre National Hospitalier et Universitaire Hubert Koutoukou Maga à Cotonou. Ces souches sont identifiées d’abord par la galerie API® Staph, puis par la spectrométrie de masse MALDI-TOF et analysées pour leur susceptibilité aux antibiotiques et leur capacité à produire des facteurs de virulence. Cette partie de l’étude a montré que les espèces les plus impliquées dans les infections à SCN au Bénin sont : S. haemolyticus et S. epidermidis suivi d’autres espèces comme S. cohnii, S. sciuri, S. arlettae, S. capitis. Nous avons aussi apporté la preuve de la multi-résistance des souches aux antibiotiques, ainsi que de la présence d’au moins un, voire plusieurs facteurs de virulence tels que la protéase, l’estérase, l’hémolysine, la leucotoxine et l’entérotoxine staphylococcique C chez 44% des souches testées particulièrement dans les souches hospitalières isolées d’hémocultures. Ensuite, nous avons caractérisé un nouveau facteur de virulence identifié chez deux souches de S. epidermidis : l’entérotoxine staphylococcique C nommée SECepi qui a été dosée à environ 100 µg/mL dans les surnageants de culture bactérienne. Le gène secepi est constitué de 801 pb correspondant à 266 acides aminés. Sur la base des résultats de la comparaison d'homologie entre la chaîne peptidique de SECepi et les séquences déjà connues, nous avons constaté que SECepi est proche de SEC3 de la souche de S. aureus Mu3, avec trois substitutions d'acides aminés dans le peptide signal et neuf substitutions d'acides aminés dans la protéine mature. Cependant, plusieurs résidus qui sont impliqués dans la formation du complexe trimoléculaire CMH-SEC-TCR sont conservés dans SECepi. L’analyse de la protéine recombinante (rSECepi) révèle une parenté antigénique et une forte homologie structurale prédite avec SECaureus. De plus, cette toxine présente les activités biologiques caractéristiques d'un superantigène (SAg) incluant la stimulation de la mitogénicité et de la production concomitante de fortes doses de cytokines pro-inflammatoires et suppressives chez des lymphocytes T humains activés. Par ailleurs, SECepi résiste assez bien au chauffage à 100°C et à la digestion par les enzymes gastro-intestinales telles que la pepsine et la trypsine. Ces résultats fournissent la preuve que SECepi peut agir comme un superantigène chez l'hôte humain bien que le type sauvage comporte plusieurs mutations chez S. epidermidis. L’étude du dossier médical de l’un des patients a montré que l’entérotoxine produite par la souche de S. epidermidis a bien pu être à l’origine d’éléments de gravité du tableau clinique présenté par ce dernier à son admission en hospitalisation. Enfin, l’analyse génomique des deux souches toxinogènes de S. epidermidis, ainsi que leur aptitude à former du biofilm, confirment les possibilités variées d’échanges génétiques entre cette espèce et S. aureus. Cette thèse souligne l'importance de la surveillance des infections à SCN chez l’homme parce que certaines souches, à l’instar de S. aureus, produisent des facteurs de virulence pouvant aggraver l’état générale l’hôte. / Coagulase-negative staphylococci (CNS) are generally considered as opportunistic pathogens with low virulence. However, previous studies have reported pathogenicity of some strains similar to that observed in S. aureus. This thesis aims to contribute to the importance of SCN in severe primitive infections. First, we evaluated the pathogenic potential of clinical CNS strains in Benin. To achieve this objective, CNS associated with various severe clinical infections were collected over at the Hubert Koutoukou Maga National Hospital and University Center in Cotonou. These strains are identified as well as their susceptibility to antibiotics and their ability to produce virulence factors. This part of the study showed that the most involved species in Benin are: S. haemolyticus and S. epidermidis followed by other species such as S. cohnii, S. sciuri, S. arlettae, S. capitis. We also demonstrated the multi-resistance of strains to antibiotics, as well as the presence of potential virulence factors such as protease, esterase, hemolysin, leukotoxin and, enterotoxin Staphylococcal C in 44% of strains tested particularly in hospital strains isolated from blood cultures. We, then, characterized a new virulence factor identified in two strains of S. epidermidis: staphylococcal enterotoxin C called SECepi, which was secreted at ~100 μg/mL in bacterial culture supernatants. The secepi gene consists of 801 bp corresponding to 266 amino acids. On the basis of the comparison between the peptide chain of SECepi and the already known peptide sequences of the SEC, we found that SECepi is close to SEC3 of S. aureus Mu3 strain with three amino acids substitutions in the signal peptide and nine amino acid substitutions in the mature protein. However, most residues involved in formation of the tri-molecular complex CMH-SEC-TCR are conserved in SECepi. Analysis of the recombinant protein (rSECepi) revealed antigenic relationships and a strong structural homology is predicted with SECaureus. Moreover, this toxin exhibits the biological activities characteristic of a SAg including the stimulation of the mitogenicity and the concomitant production of high doses of pro-inflammatory and suppressive cytokines in activated human T lymphocytes. Moreover, SECepi is resistant to heating at 100 °C and digestion by gastrointestinal enzymes such as pepsin and trypsin. These results provide evidence that SECepi can act as a superantigen in humans although the wild type has several mutations in S. epidermidis. The study of the medical record of one of the patients showed that the enterotoxin produced by the strain of S. epidermidis might be at the origin of severity of the clinics presented at hospital admission. Finally, genomic analysis of the two toxigenic S. epidermidis strains confirms the varied possibilities of genetic exchange between this species and S. aureus. This thesis underscores the importance of monitoring CNS infections in humans because some strains, like S. aureus, produce virulence factors that can aggravate the overall host condition.

A pesquisa de Staphylococcus spp. coagulase negativa (CNS) em alimentos não é prevista na legislação, entretanto, estas bactérias têm emergido como patógenos oportunistas e sua capacidade enterotoxigênica já foi documentada. O queijo destaca-se entre os principais derivados lácteos associados a intoxicações alimentares e a presença de cepas enterotoxigênicas do gênero Staphylococcus neste alimento representa um risco ao consumidor. O queijo colonial, tradicionalmente consumido pelos gaúchos, não possui regulamento técnico específico e poucos são os estudos relacionados ao risco do consumo desse alimento, bem como, à identificação de micro-organismos presentes nessa matriz. Sendo assim, os objetivos do presente estudo foram: (i) identificar as espécies de Staphylococcus spp. coagulase negativa, presentes em queijo colonial inspecionado; (ii) pesquisar a presença de genes codificadores de enterotoxinas clássicas (SE), bem como de resistência à penicilina e à meticilina nas cepas isoladas desta matriz. Para tanto, no período de novembro de 2014 a maio de 2015, foram analisadas 205 amostras de queijos coloniais inspecionados, sendo 121 adquiridas em Feiras Modelo e 84 em bancas do Mercado Público de Porto Alegre, compreendendo 17 marcas distintas. O isolamento inicial de Staphylococcus spp. foi realizado de acordo com o protocolo ISO 6888-1:1999, adicionado da triagem fenotípica para CNS. A identificação genotípica dos isolados foi realizada pela amplificação da região V1-V2 do gene 16S rRNA, seguida de sequenciamento e comparação das sequências obtidas no GenBank. A pesquisa de genes de enterotoxinas clássicas foi realizada por amplificação dos genes sea, seb, sec, sed e see. A determinação de resistência à penicilina foi avaliada a partir da amplificação do gene blaZ. Para resistência à meticilina, foi realizado teste de triagem frente à cefoxitina, e confirmação pela pesquisa do gene mecA. O armazenamento sob refrigeração foi observado em quase 90% das amostras coletadas. Entre as 179 colônias retiradas do ágar Baird-Parker, 59 apresentaram-se fenotipicamente compatíveis com CNS e foram identificadas genotipicamente. Treze espécies foram identificadas, sendo Macrococcus caseolyticus (40%) a mais frequente. Das 35 cepas confirmadas como CNS, S. equorum e S. vitulinus foram as espécies predominantes seguidas de S. hyicus, S. saprophyticus e S. epidermidis. O gene blaZ foi detectado em cinco cepas de CNS e em uma cepa de M. caseolyticus, sendo relativamente mais frequente em S. hyicus e S. epidermidis. O gene mecA não foi detectado. Oito cepas de CNS amplificaram algum gene para SE, sendo seb o mais frequente, seguido por sed, sea e see. O gene para enterotoxina C não foi detectado. Onze cepas apresentaram pelo menos um dos genes investigados, das quais, seis cepas apresentaram genes para SE e blaZ, concomitantemente. Os perfis seb/blaZ (n=4) e blaZ (n=3) foram os mais frequentes. Foi possível confirmar a diversidade de Staphylococcus spp. coagulase negativa em queijos coloniais inspecionados, além da baixa frequência de cepas carreadoras de genes para enterotoxinas clássicas e resistência à penicilina e à meticilina. / The investigation of coagulase-negative Staphylococcus spp. (CNS) is not included in food monitoring; although these bacteria have emerged as significant opportunistic pathogens and their toxigenic capacity has been documented. Among the dairy products, cheese features as one of the most involved in food poisoning outbreaks. The presence of enterotoxigenic strains of Staphylococcus in this food therefore represents a hazard for the consumers. Colonial cheese, which is a traditionally consumed cheese type in Rio Grande do Sul, does not have a specific technical regulation, and there are few studies targeting the risk for consumers, or aiming to identify its typical microbiota. Thus, the objectives of this study were: (i) to identify coagulase-negative Staphylococcus spp. species in inspected colonial cheese (ii) to investigate the presence of genes encoding classical enterotoxins (SE), and resistance to penicillin and methicillin in strains obtained from this food. For this purpose, from November 2014 to May 2015, 205 cheese samples were analyzed, 121 of which were acquired in street fairs and 84 in Central Market. The samples belonged to 17 different brands. The isolation of Staphylococcus spp. was performed according to the ISO 6888-1: 1999 protocol, followed by the phenotypic screening of CNS. The genotype identification of the isolates was performed by amplification of the V1-V2 region of the 16S rRNA gene, followed by sequencing and the sequences comparison with the GenBank database. Classical enterotoxin genes were investigated by amplification of sea, seb, sec, sed and see genes. The determination of penicillin resistance was evaluated by the amplification of blaZ gene. For methicillin resistance, a screening test with cefoxitin was conducted followed by confirmation through the mecA amplification. The majority (89,7%) of the collected samples were stored under refrigeration. Among the 179 atypical colonies obtained from Baird-Parker agar, 59 were phenotypically compatible with CNS and were further subjected to genotyping. Thirteen bacterial species were identified, being Macrococcus caseolyticus the most frequent (40%). Thirty-five strains were confirmed as CNS, being S. equorum and S. vitulinus the most prevalent followed by S. hyicus, S. saprophyticus and S. epidermidis. The gene blaZ was detected in five strains of CNS and in one strain of M. caseolyticus, being relatively more frequent in S. hyicus and S. warneri. The mecA gene was not detected. Eight CNS strains amplified SE gene: SEB was the most frequent, followed by SED, SEA and SEE. There was no enterotoxin C gene detected. Eleven strains carried at least one of the genes investigated; six strains presented genes for SE and blaZ, concomitantly. The profiles SEB/blaZ (n = 4) and blaZ (n = 3) were the most frequent. The diversity of CNS in inspected colonial cheeses was confirmed. In addition, the low frequency of strains carrying genes for enterotoxins and resistance to penicillin and methicillin was observed.

Resumo: Entre agosto de 2005 e dezembro de 2006, foram obtidas 245 estirpes de Staphylococcus aureus isoladas de amostras de leite de vacas com mastite, de óstios papilares da glândula mamária e de insufladores da ordenhadeira, procedentes de um rebanho bovino produtor de leite tipo B. Com a finalidade de monitorar as estirpes de S. aureus envolvidas em casos de mastite bovina por meio da verificação da relação epidemiológica existente entre as estirpes isoladas, especialmente com vistas aos sítios de localização e vias de transmissão, as estirpes foram submetidas à Eletroforese de Campo Pulsado (PFGE), à amplificação das seqüências codificadoras (sea, seb, sec, sed e tst), por intermédio da Reação em Cadeia da Polimerase (PCR), e suas sensibilidades in vitro a 12 antimicrobianos foram determinadas. Os resultados obtidos revelaram 51 diferentes perfis, sendo que a resistência à penicilina foi a predominante entre as 179 (73,1%) estirpes de S. aureus, quando considerada de forma particular (54,8%) ou em conjunto (29,4%). As 66 (26,9%) estirpes restantes foram sensíveis aos 12 antimicrobianos testados e a vancomicina foi o único princípio ativo que se mostrou eficiente a 100% das estirpes testadas. A PFGE revelou 39 pulsotipos distintos, dos quais 25 (64,1%) encontraram-se distribuídos nas 137 (55,9%) estirpes obtidas do leite. Dentre estas, 92 (67,1%) estirpes apresentaram resistência a um ou mais antimicrobianos e foram agrupadas em 22 (88,0%) pulsotipos distintos. Foi observado, também, por meio da PFGE, que nenhum pulsotipo foi isolado por mais de três colheitas consecutivas e que somente o pulsotipo 29 foi identificado em 5 (31,2%) colheitas...(Resumo completo, clicar acesso eletrônico abaixo) / Abstract: Two hundred and forty five Staphylococcus aureus strains were isolated between August of 2005 and December of 2006 from samples collected from a type-B milk-producing herd. Samples encompassed milk collected directly from mastitic cows, papillas osteuns of mammary glands, and milking machine cups. Samples were subjected to Pulsed Field Gel Electrophoresis (PFGE) to monitor for the strains of S. aureus and to determine epidemiologic relationships between the isolated strains, taking into account the different precedence of strains. PFGE was used to monitor the presence of specific coding sequences (i.e., sea, seb, sec, sed, and tst) in the milk samples using polymerase chain reaction (PCR) amplification. Moreover, sensitivity of strains to 12 different antibiotics was determined in vitro. Results revealed the presence of 51 different PFGE profiles of S. aureus in the samples, and highlighted 179 (73.1%) penicillin resistant strains. Nonetheless, the 66 (26.9%) other strains were sensitive to all 12 antibiotics tested, and vancomycin was the only antibiotic effective against all tested strains. PFGE also revealed 39 distinct peaks with 25 of them (64.1%) being present in 137 (55.9%) strains obtained from milk. Of these strains, 92 (67.1%) were resistant to one or more antibiotics, and were further grouped in 22 (88.0%) distinct peaks. Additionally, PFGE revealed the presence of no distinct peaks in samples from three consecutive collection times, and that peak 29 was the only one identified in 5 collection times (31.2%). Importantly, PGFE also indicated that in the periods A and H, which corresponded to 12.5% of the total time points, the isolated strains from one collection day (samples from all 3 sources) all had the peaks 2 and 12, respectively...(Complete abstract, click electronic access below) / Orientador: Antonio Nader Filho / Coorientador: Luiz Francisco Zafalon / Banca: Carlos Augusto Fernande de Oliveira / Banca: Naiá Carla Marchi de Rezende Lago / Banca: Paulo Francisco Domingues / Banca: Manoel Victor Franco Lemos / Doutor

A resposta proliferativa das células mononucleares do sangue periférico dos adultos com dermatite atópica mostrou-se diminuída após estímulos com mitógenos (enterotoxinas estafilocócicas A e B, "pokeweed" e fitohemaglutinina) e antígenos (toxóide tetânico e Candida albicans). A correlação positiva dos níveis séricos de interleucina-18, IgE e escore de gravidade da doença sugerem que esta citocina seria um marcador de atividade da dermatite atópica do adulto / A reduced proliferative response of peripheral blood mononuclear cells in adults with atopic dermatitis was detected when stimuli with mitogens (staphylococcal enterotoxins A and B, phytohemaglutinin, pokeweed), and with antigens (tetanus toxoid and Candida albicans) were performed. A positive correlation of interleukin-18, IgE levels and severity scores of the disease suggest that this cytokine could be a marker of disease activity in adult atopic dermatitis

A resposta proliferativa das células mononucleares do sangue periférico dos adultos com dermatite atópica mostrou-se diminuída após estímulos com mitógenos (enterotoxinas estafilocócicas A e B, "pokeweed" e fitohemaglutinina) e antígenos (toxóide tetânico e Candida albicans). A correlação positiva dos níveis séricos de interleucina-18, IgE e escore de gravidade da doença sugerem que esta citocina seria um marcador de atividade da dermatite atópica do adulto / A reduced proliferative response of peripheral blood mononuclear cells in adults with atopic dermatitis was detected when stimuli with mitogens (staphylococcal enterotoxins A and B, phytohemaglutinin, pokeweed), and with antigens (tetanus toxoid and Candida albicans) were performed. A positive correlation of interleukin-18, IgE levels and severity scores of the disease suggest that this cytokine could be a marker of disease activity in adult atopic dermatitis

INTRODUÇÃO: A dermatite atópica (DA) é uma doença cutânea inflamatória, acompanhada por prurido intenso e xerose cutânea. A etiopatogenia da DA é multifatorial, envolvendo fatores genéticos, ambientais e imunológicos, dentre outros. OBJETIVOS: Avaliar a influência das enterotoxinas A e B do Staphylococcus aureus (SEA e SEB) na resposta mediada por células Th17 e Th22 nos indivíduos adultos com DA. MÉTODOS: Foram selecionados 38 pacientes adultos com DA e um grupo controle com 40 indivíduos adultos, pareados por idade e gênero Os métodos utilizados foram: 1) ELISA: dosagem dos níveis séricos de IL-6, IL-17, IL-22 e IL-12p40/IL-23 e em sobrenadantes de culturas de células mononucleares do sangue periférico (PBMC) estimuladas com SEA e SEB; 2) Imuno-histoquímica: análise da expressão de IL-17 em fragmentos de pele; 3) Citometria de fluxo: a) análise das citocinas circulantes em amostras de soro: IL-2, IL-4, IL-5, IL-6, IL-10, TNF, IL-17A e IFN-y b)avaliação das células T CD4+ mono e polifuncionais secretoras de IL-17, IL-22, TNF, IFN-y, MIP-1beta, e expressão do marcador de ativação celular CD38; c) células Th22 e Tc22 estimuladas com SEA e SEB. RESULTADOS: 1) Através do ELISA, a secreção de IL-22 sérica e em PBMC induzidas por SEA e SEB foi significativamente mais elevada, quando comparada ao grupo controle; 2) houve aumento na expressão de IL-17 em amostras de pele de doentes de DA através da imuno-histoquímica; 3) Através da citometria de fluxo, foram detectados: a) níveis séricos de IL-2, 5, 6, 10, 17A e IFN-y elevados no grupo com DA em relação aos controles; houve diferença significativa nos níveis circulantes de IL-17A nos pacientes com DA moderada e grave; b) na avaliação monofuncional das células T CD4+ sob estímulo de SEA/SEB, houve redução da expressão das citocinas IFN-y, IL-17A, IL-22 ou TNF na DA, quando comparadas ao grupo controle; na análise polifuncional das células T CD4+/CD8+, ocorreu redução da resposta na DA em relação aos controles; nos pacientes atópicos encontramos aumento da resposta em situação basal na dependência de CD38, e redução na resposta frente a SEA/SEB na ausência de CD38; c) encontramos resposta reduzida das células Th22, e elevada de células Tc22 frente aos estímulos SEA e SEB, nos pacientes com DA. CONCLUSÕES: O estudo corrobora o papel patogênico das enterotoxinas estafilocócicas na DA. A ativação crônica com superantígenos estafilocócicos pode contribuir com a alta frequência de células T CD4+ CD38+ polifuncionais, e com a resposta polifuncional anérgica, mediadas por células T CD38- / BACKGROUND: Atopic dermatitis (AD) is an inflammatory skin disease with intense itching and xerosis. AD pathogenesis is multifactorial, involving genetic, environmental, and immunological factors, among others. OBJECTIVES: To evaluate the influence of enterotoxins A and B from Staphylococcus aureus (SEA and SEB) in Th17 and Th22 cell response in adults with AD. METHODS: We evaluated 38 adult patients with AD, and a control group of 40 adults, age and gender matched. Assays: 1) ELISA: evaluation of IL-6, IL-17, IL-12p40/IL-23 and IL-22 serum levels and in supernatants of mononuclear cell cultures from peripheral blood (PBMC), stimulated with SEA/SEB; 2) Immunohistochemistry: analysis of IL-17 expression in skin specimens; 3) Flow cytometry: a) analysis of circulating cytokines in serum samples: IL-2, IL-4, IL-5, IL-6, IL-10, TNF, IL-17A and IFN-y b) evaluation of mono and polyfunctional TCD4+ cells that secrete IL-17, IL-22, TNF, IFN-y, MIP-1beta, and expression of the activation marker CD38; c) analysis of Tc22 and Th22 cells stimulated with SEA and SEB. RESULTS: 1) Secretion of IL-22 in the serum and from supernatants of cell cultures from PBMC, stimulated with SEA and SEB were higher in AD patients, when compared to the control group by ELISA; 2) there was an increase of IL-17 expression in skin samples by immunohistochemistry; 3) Flow cytometry showed: a) elevated serum levels of IL-2, 5, 6, 10, 17A and IFN-y in AD, when compared to controls; there was a significant difference in circulating levels of IL-17A in patients with moderate and severe disease; b) monofunctional evaluation of T CD4+ cells under SEA/SEB stimuli showed reduced expression of IFN-y, IL-17A, IL-22 or TNF cytokines in AD, compared to controls; the same was observed for polyfunctional CD4+/CD8+ T cells analysis, exhibiting a diminished response in AD. In atopic patients under basal conditions, there was an augmented CD38- dependent response and reduced pattern to SEA/SEB in the absence of CD38; c) finally, we observed a reduced response of Th22 cells and enhanced Tc22 cells under SEA/SEB stimuli in patients with AD. CONCLUSIONS: This study corroborates the pathogenic role of staphylococcal enterotoxins in AD. Chronic activation with staphylococcal superantigens may contribute to the high frequency of polyfunctional CD4 +CD38+ T cells and with the anergic polyfunctional response mediated by T CD38- T cells

L’entérotoxine B staphylococcique (SEB) est une toxine entérique hautement résistante à la chaleur et est responsable de plus de 50 % des cas d’intoxication d’origine alimentaire par une entérotoxine. L’objectif principal de ce projet de maîtrise est de développer et valider une méthode basée sur des nouvelles stratégies analytiques permettant la détection et la quantification de SEB dans les matrices alimentaires. Une carte de peptides tryptiques a été produite et 3 peptides tryptiques spécifiques ont été sélectionnés pour servir de peptides témoins à partir des 9 fragments protéolytiques identifiés (couverture de 35 % de la séquence). L’anhydride acétique et la forme deutérée furent utilisés afin de synthétiser des peptides standards marqués avec un isotope léger et lourd. La combinaison de mélanges des deux isotopes à des concentrations molaires différentes fut utilisée afin d’établir la linéarité et les résultats ont démontré que les mesures faites par dilution isotopique combinée au CL-SM/SM respectaient les critères généralement reconnus d’épreuves biologiques avec des valeurs de pente près de 1, des valeurs de R2 supérieure à 0,98 et des coefficients de variation (CV%) inférieurs à 8 %. La précision et l’exactitude de la méthode ont été évaluées à l’aide d’échantillons d’homogénat de viande de poulet dans lesquels SEB a été introduite. SEB a été enrichie à 0,2, 1 et 2 pmol/g. Les résultats analytiques révèlent que la méthode procure une plage d’exactitude de 84,9 à 91,1 %. Dans l’ensemble, les résultats présentés dans ce mémoire démontrent que les méthodes protéomiques peuvent être utilisées efficacement pour détecter et quantifier SEB dans les matrices alimentaires. Mots clés : spectrométrie de masse; marquage isotopique; protéomique quantitative; entérotoxines / Staphylococcal enterotoxin B is a highly heat-resistant enteric toxin and it is responsible for over 50% of enterotoxin food poisoning. It represents a particular challenge during food processing since, even if the bacteria have been destroyed, the biological activity of the toxin remains unchanged. The objective of this study was to develop and validate a new method based on a novel proteomic strategy to detect and quantify SEB in food matrices. Tryptic peptide map was generated and 3 specific tryptic peptides were selected and used as surrogate peptides from 9 identified proteolytic fragments (sequence coverage of 35%). Peptides were label with light and heavy form of acetic anhydride to create an isobaric tag that will allow quantification. The linearity was tested using mixtures of different molar ratios and the results showed that measurements by LC-MS/MS were within generally accepted criteria for bioassays with slope values near to 1, values of R2 above 0.98 and less than 8% coefficient of variation (%CV). The precision and accuracy of the method were assessed using chicken meat homogenate samples spiked with SEB at 0.2, 1 and 2 pmol/g. The results indicated that the method can provide accuracy within 84.9 – 91.1% range. Overall, the results presented in this thesis show that proteomics-based methods can be effectively used to detect, confirm and quantify SEB in food matrices. Keywords: mass spectrometry; stable isotope labeling; quantitative proteomics; enterotoxins

Made available in DSpace on 2014-06-11T19:32:54Z (GMT). No. of bitstreams: 0 Previous issue date: 2007-09-21Bitstream added on 2014-06-13T20:24:20Z : No. of bitstreams: 1 thuler_amg_dr_jabo.pdf: 1407432 bytes, checksum: d7e6ed286b2d4a2ad8e9b2120b24b7ca (MD5) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / O trabalho foi desenvolvido no Laboratório de Genética de Bactérias e Biotecnologia Aplicada (LGBBA) da FCAV-UNESP. Foram caracterizados geneticamente, por PCR, isolados de Bacillus thuringiensis, provenientes de três coleções brasileiras, quanto aos tipos de genes cry1, avaliando-se o efeito dos mesmos sobre uma população de Plutella xylostella caracterizando-se também os isolados de B. thuringiensis quanto à presença de enterotoxinas HBL, NHE e o regulador pleitrópico PLC, por verificação biomolecular, avaliando a variabilidade, bem como a estruturação genética de populações de B. thuringiensis, por PCR-RFLP. Verificou-se que existe uma distribuição homogênea das subclasses cry1 dentro do banco de isolados de B. thuringiensis, com maior porcentagem de isolados portadores dos genes cry1Ab (42,12%) e com menor porcentagem de representantes da subclasse cry1Db (0,6%). Nos bioensaios observou-se 100% de mortalidade para lagartas de P. xylostella com os isolados utilizados, indicando que combinações de tipos diferentes de genes cry1 apresentam ação tóxica para larvas de P. xylostella. Analisando a estrutura populacional de B. thuringiensis foram obtidos 78 haplótipos, definidos para as populações das diferentes coleções, e 76 haplótipos, definidos para as populações de diferentes regiões brasileiras, retratando a variabilidade genética para os loci hblA, plcR, nheBC e cry1 analisados. Segundo valores FSTs, de comparação duas a duas, diferenças significativas entre coleções e populações de B. thuringiensis provenientes das regiões brasileiras foram verificadas. Mesmo assim, alguns grupos formados são constituídos por uma população clonal de isolados da bactéria. / The work was developed in the Laboratory of Bacterias’ Genetics and Applied Biotechnology (LGBBA) at UNESP/ Jaboticabal Campus. There were genetically characterized, by PCR, isolates of B. thuringiensis, belonging to three Brazilian collections basead on cry1 gene content, evaluating their effects on Plutella xylostella. They were also characterized concerning their enterotoxins production such as HBL, NHE and the PLC virulence factor, using molecular techniques, so as to evaluate their gene diversities, as well as their population genetic, using the PCR-RFLP approach. It was observed a homogeneous distribution of the cry1 subclasses within B. thuringiensis strain collections studied, with bigger percentage of isolates showing the cry1Ab genes (42.12%) and with lower percentage of isolates for subclass cry1Db (0.6%). The bioassays have revealed 100% mortality to P. xylostella larvae meaning that the effectiveness of B. thuringiensis as a biological control agent does not depend at the cry genes content. When the B. thuringiensis population structure was considered, 78 haplotypes were defined for the strains contents of different collections and 76 haplotypes were defined for strains of different Brazilian regions, exhibiting the great genetic variability for hblA, plcR, nheBC and cry1 loci. According to the FSTs values for establish pair comparisons, significant differences among the B. thuringiensis collections and populations, were observed. Nevertheless some of the formed groups were considered as bacterial clonal population.