Düsseldorf, Universiẗat, Diss., 2002.

Les mycoplasmes sont des bactéries à petit génome dérivées d’ancêtres à Gram positif par une succession de pertes de matériel génétique. Il a longtemps été considéré que la réduction génétique était la seule force régissant l’évolution de ces bactéries, cependant, des transferts horizontaux de grandes régions chromosomiques au sein et entre les espèces de mycoplasmes ont été récemment mis en évidence. Des éléments conjugatifs et intégratifs (ICE) découverts chez certaines espèces de mycoplasme pourraient être à l’origine de ces transferts. Ces ICEs codent les systèmes nécessaires pour leur excision, leur transfert conjugatif et leur intégration dans la cellule receveuse.Mycoplasma hominis est un mycoplasme commensal des voies génitales qui peut être responsable d’infections gynécologiques, d’infections néonatales et d’infections extragénitales. L’analyse préliminaire de génomes de M. hominis avait montré la présence de régions codantes caractéristiques des ICEs. Les objectifs de cette thèse étaient de rechercher et caractériser les ICEs chez 12 isolats cliniques de M. hominis entièrement séquencés et de déterminer la prévalence de ces ICEs au sein de l’espèce M. hominis. Pour cela, une étude rétrospective sur une période de 6 ans a été menée sur des isolats cliniques obtenus au CHU de Bordeaux. Les concentrations minimales inhibitrices des tétracyclines et des fluoroquinolones ainsi que les mécanismes de résistance ont été déterminés, permettant de disposer d’une collection d’isolats cliniques caractérisés pour l’étude des ICEs.Des ICEs de près de 30 kpb ont été trouvés en une ou plusieurs copies dans sept des 12 souches de M. hominis séquencées. Seulement cinq de ces ICEs semblaient fonctionnels puisqu’une forme circulaire a pu être détectée. Tous les ICEs de M. hominis présentaient une structure similaire avec un module spécifique de M. hominis d’environ 4-kpb, codant des protéines ayant des caractéristiques structurelles similaires à des effecteurs TAL (transcription activator-like), impliqués dans la reconnaissance de nucléotides et dans la transduction de signaux chez les bactéries symbiotiques. La caractérisation des mécanismes de résistance aux antibiotiques des isolats cliniques de M. hominis collectés au CHU de Bordeaux nous a permis de disposer d’une collection de 183 isolats isolés entre 2010 et 2015, parmi lesquels 14,8% étaient porteur du gène tet(M) responsable de la résistance aux tétracyclines, 2,7% étaient résistant à la lévofloxacine et 1,6% étaient résistants à la moxifloxacine par mutation des gènes de la topoisomérase IV et de l’ADN gyrase. Le screening de 120 de ces isolats cliniques a révélé une prévalence élevée des ICEs dans l’espèce M. hominis, mesurée à 45%. Il n’y avait pas de prédominance des ICEs dans les isolats portant le gène tet(M), suggérant que les ICEs n’étaient pas responsables de la dissémination de la résistance à la tétracycline.Des expériences complémentaires de conjugaison seront nécessaires pour confirmer la fonctionnalité des ICEs retrouvés dans l’espèce M. hominis. Cependant, la forte prévalence et le caractère très conservé des ICEs chez M. hominis suggèrent que ces ICEs pourraient conférer un avantage sélectif pour la physiologie ou la physiopathologie de la bactérie. Ce travail ouvre ainsi la voie à de futures études qui permettront une meilleure compréhension des transferts horizontaux de gènes et des facteurs de virulence chez M. hominis. / Mycoplasmas are small-genome bacteria derived from Gram-positive ancestors by a succession of genetic material losses. It has long been considered that genetic reduction was the only force governing the evolution of these bacteria, however, horizontal transfers of large chromosomal regions within and between mycoplasma species have recently been reported. Conjugative and integrative elements (ICE) found in some species of mycoplasma may be responsible for these transfers. These ICEs encode the systems necessary for excision, conjugative transfer and integration into a recipient cell.Mycoplasma hominis is a commensal genital mycoplasma that can be responsible for gynecological infections, neonatal infections and extragenital infections. Preliminary analysis of M. hominis genomes had showed the presence of coding regions characteristic of ICEs. The objectives of this thesis were to search for and characterize ICEs in one reference strain and 11 fully sequenced M. hominis clinical isolates and to determine the prevalence of these ICEs in the M. hominis species. To do so, a retrospective study over a period of 6 years was conducted on clinical isolates collected at the Bordeaux University Hospital. The minimum inhibitory concentrations of tetracyclines and fluoroquinolones as well as resistance mechanisms were determined, providing a collection of clinical isolates characterized for the study of ICEs.ICEs of 27-30 kpb were found in one or two copies in seven of the 12 M. hominis sequenced strains. Only five of these ICEs seemed functional since circular forms of extrachromosomal ICE were detected. All M. hominis ICEs exhibited a similar structure consisting of a 4.0-5.1 kb module composed of five to six juxtaposed CDSs, encoding proteins that share common structural features with transcription activator-like (TAL) effectors, involved in polynucleotide recognition and signal transduction in symbiotic bacteria. The characterization of antibiotic resistance mechanisms in M. hominis clinical isolates collected at Bordeaux University Hospital enabled us to obtain a collection of 183 isolates isolated between 2010 and 2015, of which 14.8% harbored the tet(M) gene responsible for tetracycline resistance, 2.7% were resistant to levofloxacin and 1.6% were resistant to moxifloxacin by mutation in topoisomerase IV and DNA gyrase genes. Screening of 120 of these clinical isolates revealed a high prevalence of ICEs in M. hominis, measured to be 45%. The proportion of ICEs was not higher in isolates carrying the tet (M) gene, suggesting that ICEs were not responsible for the spread of tetracycline resistance.Additional mating experiments will be necessary to confirm the functionality of the ICEs found in the M. hominis species. However, the conserved and specific structure of M. hominis ICEs and the high prevalence in clinical strains suggest that these ICEs may confer a selective advantage for the physiology or pathogenicity of the bacteria. This work opens the way for future studies that will provide a better understanding of horizontal gene transfers and virulence factors in M. hominis.

Mycoplasma hominis est un pathogène humain opportuniste responsable d’infections génitales et néo-natales. Modifier génétiquement cette bactérie est nécessaire afin de comprendre les mécanismes de virulence et d’infection de ce pathogène. Il n’existe à ce jour aucun outil moléculaire efficace permettant de manipuler le génome de M. hominis, limitant les recherches sur sa pathogénicité et son métabolisme particulier reposant sur l’arginine. De nouvelles technologies rassemblées sous le terme de Biologie de Synthèse (BS) ont récemment émergé, offrant des perspectives inédites pour l’étude des mycoplasmes en permettant de modifier leurs génomes à grande échelle et de produire des souches mutantes. Ces travaux menés au J. Craig Venter Institute (JCVI, USA) ont montré que le génome de mycoplasmes apparentés pouvait être cloné et manipulé dans la levure avant d’être transplanté dans une cellule receveuse. La levure sert d’hôte d’accueil temporaire pour modifier le génome de la bactérie. Cette approche novatrice ouvre de nombreuses perspectives dans le cadre du développement de la génomique fonctionnelle chez les mycoplasmes pour lesquels les outils génétiques efficaces sont peu nombreux. Le but de cette thèse a été d’adapter pour la première fois certains outils de BS à M. hominis dans le but de créer des mutants déficients pour une fonction donnée. Pour cela, le génome de la souche type de M. hominis PG21 (665 kb) a été cloné dans la levure Saccharomyces cerevisiae par « Transformation-Associated Recombination cloning » (TAR-cloning). Deux clones (B3-2 et B3-4) de levure possédant le génome complet de M. hominis ont été validés par analyse en PCR simplex, PCR multiplex et électrophorèse en champs pulsé (PFGE). Ces clones levures ont ensuite été propagés en milieu sélectif durant 180 générations (30 passages), afin d’évaluer la stabilité du génome bactérien dans son hôte. Cette expérience a montré que (i) si la taille du génome de M. hominis ne variait pas au cours des premiers passages, elle diminuait progressivement à partir du dixième passage (≈60 générations), et que (ii) les zones du génome enrichies en séquence répétées étaient préférentiellement perdues. En tenant compte de ces résultats, le génome de M. hominis a été modifié chez le clone B3-4 par la technique « Clustered Regularly Interspaced Short Palindromic Repeats/Cas9 » (CRISPR/Cas9) lors de passages précoces. Des clones de S. cerevisiae possédant un génome de M. hominis PG21 complet délété du gène vaa, codant une protéine d’adhésion majeure, ont été ainsi produits. La dernière étape de cette approche consistait à transplanter le génome modifié dans une cellule receveuse de M. hominis ou de Mycoplasma arthritidis, espèce phylogénétiquement la plus proche de M. hominis. Aucun protocole de transformation de M. hominis n’étant disponible au début de nos travaux, cette étape constituait un verrou majeur dans la mise en place des outils de BS chez cette espèce. Ce verrou a été en partie levé puisqu’une méthode de transformation de M. hominis basée sur du polyéthylène glycol (PEG) et mettant en jeu le plasposon pMT85 (plasmide contenant un transposon conférant la résistance à la tétracycline) a été mise au point au laboratoire. Cette technique de transformation, développée pour la souche de référence M. hominis M132 (745 kb) reste encore peu efficace ; elle est néanmoins reproductible et a permis d’obtenir des mutants d’intérêt de M. hominis. Le transformant n°28-2 a, ainsi, été muté dans le gène Mhom132_2390, codant le précurseur de la protéine P75, une adhésine putative de M. hominis. Le séquençage des génomes complets d’autres transformants a révélé l’insertion de multiples copies du transposon et la présence d’évènements de duplication et d’inversion de larges fragments d’ADN dans au moins deux génomes de M. hominis. / Mycoplasma hominis is an opportunistic human pathogen responsible for genital and neonatal infections. Genetically modifying this bacterium is necessary to understand the virulence and infection mechanisms of this pathogen. There is currently no effective molecular tool to engineer the genome of this bacterium, limiting research on its pathogenicity and its peculiar metabolism based on arginine.New technologies have recently emerged in the field of Synthetic Biology (BS), offering new perspectives for the study of mycoplasmas by allowing large scale genome modifications and the production of mutant strains. Work at the J. Craig Venter Institute (JCVI, USA) has shown that the genome of related mycoplasmas can be cloned and manipulated in yeast before being transplanted into a recipient cell. The yeast serves as a temporary host to modify the genome of the bacterium. This innovative approach opens many perspectives in the development of functional genomics in mycoplasmas for which there are few effective genetic tools. The goal of this thesis was to adapt a number of BS tools to M. hominis for the first time, in order to create mutants deficient for a given function. To achieve this goal, the genome of the M. hominis type strain PG21 (665 kb) was cloned into the yeast Saccharomyces cerevisiae by Transformation-Associated Recombination cloning (TAR-cloning). Two yeast clones (B3-2 and B3-4) possessing the complete genome of M. hominis were validated by simplex PCR, multiplex PCR and Pulsed Field Gel Electrophoresis (PFGE) analyses. These yeast clones were then propagated in a selective medium for 180 generations (30 passages) to evaluate the stability of the bacterial genome in its host. This experiment showed that (i) the size of the genome of M. hominis did not change during the first passages, it decreased progressively from the tenth passage (≈60 generations), and (ii) the enriched genome areas in repeated sequence were preferentially lost. Thus, the genome of M. hominis was modified in the B3-4 clone at early passages using the Clustered Regularly Interspaced Short Palindromic Repeats/Cas9 (CRISPR/Cas9) technology. Yeast clones with a complete M. hominis PG21 genome with a deleted vaa gene, encoding a major adhesion protein, were produced using this approach. The final step of this approach was to transplant the modified genome into a recipient cell of M. hominis or Mycoplasma arthritidis, the species phylogenetically closest to M. hominis. As no M. hominis transformation protocol was available at the beginning of our work, this step constituted a major obstacle in the implementation of BS tools in this species. This barrier has been partially lifted since a method of transformation of M. hominis based on polyethylene glycol (PEG) and involving the plasposon pMT85 (plasmid carrying a transposon conferring resistance to tetracycline) has been developed in the laboratory. This transformation technique, developed for the reference strain M. hominis M132 (745 kb) still remains not very efficient; it is nevertheless reproducible and allowed to obtain M. hominis mutants of interest. The Mhom132_2390 gene, encoding the precursor of the P75 protein, a putative adhesin of M. hominis, was effectively mutated in transformant No. 28-2. Complete genome sequencing of other transformants revealed the insertion of multiple copies of the transposon and the presence of duplication and inversion of large DNA fragments within at least two M. hominis genomes.In conclusion, this data has opened the way for the development and transposition of existing genetic modification approaches to M. hominis, previously considered as a genetically intractable bacterium.

La nature du lien qui unit les deux aspects du système immunitaire, que sont la défense de l’hôte contre les agressions extérieures et la genèse des maladies auto- immunes, n’a pas été élucidée. L’axe IL-23/Th17 joue un rôle dans les deux versants, ce qui le place en bonne position pour être un potentiel chaînon manquant. Objectif : connaître l’implication de cet axe dans un modèle infectieux, Mycoplasma hominis, et un modèle de maladie auto-immune, la sclérodermie systémique (ScS), dans lesquels il n’a pas encore été étudié. Les lipoprotéines membranaires de M. hominis sont capables d’induire une maturation des cellules dendritiques humaines. Elle s’accompagne d’une sécrétion d’IL-23 variable selon l’origine clinique des isolats, via TLR2, et d’une polarisation vers la voie Th17. Nous avons observé une augmentation de la fréquence des cellules Th17 et Th22 dans le sang périphérique des patients ScS, potentialisée par l’iloprost, via entre autres la production monocytaire d’IL-23. Dans la peau des patients ScS, il existe une augmentation des cellules produisant l’IL-17 inversement corrélé au score de fibrose cutanée. In vitro, l’IL-17 est capable d’inhiber partiellement l’expression d’α-SMA induite par le TGF-ß et d’induire la sécrétion de MMP1 par des fibroblastes dermiques humains. L’axe IL-23/IL-17 et les cellules Th17 jouent un rôle dans la défense contre M. hominis et dans la physiopathologie de la ScS. / Relationship between both aspects of the immune system, ie host defense against external aggression and genesis of autoimmune diseases, has not been elucidated. IL-23/Th17 axis plays a role in both sides, which puts him in a good position to be a potential missing link. Objective: To understand the implication of this axis in a model of infection, Mycoplasma hominis, and a model of autoimmune disease, systemic sclerosis (SSc), in which it has not yet been studied.
The membrane lipoproteins of M. hominis are capable of inducing human dendritic cell maturation. It occurs along with an IL-23 secretion changing with the clinical origin of isolates, via TLR2, and a T cell polarization towards Th17. Then we observed an increase in the Th17 and Th22 cell frequency in peripheral blood of SSc patients, further enhanced by iloprost via monocyte production of IL-23 among others. In the skin of SSc patients, we showed an increase in IL-17-producing cells with an inverse correlation to the skin fibrosis score. In vitro, IL-17 is able to partially inhibit the expression of α-SMA induced by TGF-ß and to induce the secretion of MMP1 in human dermal fibroblasts. The IL-23/IL-17 axis and Th17 cells play a role in defense against M. hominis and in the pathogenesis of SSc.

Orientador: Márcia Guimarães da Silva / Banca: Rodrigo Paupéro de Camargo Soares / Banca: Vera Lúcia Mores Rall / Não disponível / Abstract: Microbial invasion of the amniotic cavity has been described in term deliveries and its role on the immune modulation is of interest to the better understanding of the underlying labor processes. The aim of this study was to determine the prevalence of Mycoplasma hominis and Ureaplasma urealyticum in the amniotic fluid of term pregnancies and to evaluate its influence on cytokines production at the end of pregnancy. A cross sectional study was conducted with fifty five pregnant women out of labor with intact membranes and gestational age between 37 and 41 weeks seen at the Bom Jesus hospital in Ariquemes, Rondônia, between June 2009 and May 2010. Amniotic fluid samples and fragments of chorioamniotic membranes were collected at cesarean section. M. hominis and U. urealyticum detection was performed by PCR and Interleukin (IL)-1β, IL-6, IL-8, IL-10 and Tumor Necrosis Factor (TNF)- levels were determined by ELISA. Chorioamniotic membranes were submitted to histopatological analyses. Presence of M. hominis was detected in 36.4% of amniotic fluid samples and any of them was positive for U. urealyticum. Regarding cytokines levels, 63.6% and 90.9% of samples have not shown detectable concentrations of TNF- and IL-1β. The median concentration of IL-6 and IL-8 were 107.9 pg/mL (0-517.1) and 208.1 pg/mL (0-1897.4), respectively. Interleukin-1, IL-6, IL-8 and TNF- concentrations were not associated with the presence of M. hominis in amniotic fluid, regardless the gestational age. No sample had detectable IL-10 levels. The histopatological analyses have shown no chorioamnionitis in any of the membranes, only a discreet mononuclear infiltration in the decidua could be observed in 40.4% of the samples. Presence of M. hominis was detected in 36.4% of amniotic fluid samples and any of them was positive for U. urealyticum. Regarding cytokines levels, 63.6% and 90.9% of samples have not... (Complete abstact click electronic access below) / Mestre

Mycoplasmas conform most closely with the theoretical concept of 'minimum cells', existing as the smallest, free-living organisms capable of self-replication. They survive as parasites of plants, insects, animals or humans, with the most common human colonising species being Mycoplasma hominis. M. hominis has been characterised as a human pathogen responsible for a variety of infections, which pose a significant threat particularly to immunocompromised patients and neonates. However little has been elucidated about the cell physiology and molecular structure of this organism. Of interest to this study were the investigation of the heat shock response of M. hominis and the diagnostic assays used for its detection. The heat shock response is a ubiquitous physiological feature of all organisms and displays unprecedented conservation. This phenomenon is particularly evident in the 70 kDa family of heat shock proteins (hsp70) which exhibits a high degree of homology between different species. The hsp70 gene from M. hominis was cloned and preliminary partial sequencing indicated the similarity with other hsp70 homologs. The regulation of hsp70 expression at the transcriptional and translational levels was investigated. The level of hsp70 mRNA was found to increase correspondingly in response to heat shock, more visibly than the level of hsp70 protein. However imrnunochemical studies of the M. hominis hsp70 translation product demonstrated further the homology with other species. To facilitate rapid diagnosis of M. hominis infections, a PCR ELISA diagnostic assay was developed and optimised. The amplification of a conserved region of the M. hominis 16S rRNA gene was linked to subsequent hybridisation to an appropriate capture probe in a microtiter plate format. The sensitivity of the assay was comparable to other molecular assays although the PCR ELISA produces more rapid results and is less labour intensive. / Thesis (M.Sc.)-University of Natal, Pietermaritzburg, 1998.

Made available in DSpace on 2014-06-11T19:27:56Z (GMT). No. of bitstreams: 0 Previous issue date: 2011-02-28Bitstream added on 2014-06-13T20:57:18Z : No. of bitstreams: 1 ramos_bra_me_botfm.pdf: 447116 bytes, checksum: 446e118d63a97d1a69658b7e651b69aa (MD5) / Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) / Microbial invasion of the amniotic cavity has been described in term deliveries and its role on the immune modulation is of interest to the better understanding of the underlying labor processes. The aim of this study was to determine the prevalence of Mycoplasma hominis and Ureaplasma urealyticum in the amniotic fluid of term pregnancies and to evaluate its influence on cytokines production at the end of pregnancy. A cross sectional study was conducted with fifty five pregnant women out of labor with intact membranes and gestational age between 37 and 41 weeks seen at the Bom Jesus hospital in Ariquemes, Rondônia, between June 2009 and May 2010. Amniotic fluid samples and fragments of chorioamniotic membranes were collected at cesarean section. M. hominis and U. urealyticum detection was performed by PCR and Interleukin (IL)-1β, IL-6, IL-8, IL-10 and Tumor Necrosis Factor (TNF)- levels were determined by ELISA. Chorioamniotic membranes were submitted to histopatological analyses. Presence of M. hominis was detected in 36.4% of amniotic fluid samples and any of them was positive for U. urealyticum. Regarding cytokines levels, 63.6% and 90.9% of samples have not shown detectable concentrations of TNF- and IL-1β. The median concentration of IL-6 and IL-8 were 107.9 pg/mL (0-517.1) and 208.1 pg/mL (0-1897.4), respectively. Interleukin-1, IL-6, IL-8 and TNF- concentrations were not associated with the presence of M. hominis in amniotic fluid, regardless the gestational age. No sample had detectable IL-10 levels. The histopatological analyses have shown no chorioamnionitis in any of the membranes, only a discreet mononuclear infiltration in the decidua could be observed in 40.4% of the samples. Presence of M. hominis was detected in 36.4% of amniotic fluid samples and any of them was positive for U. urealyticum. Regarding cytokines levels, 63.6% and 90.9% of samples have not... (Complete abstact click electronic access below)

Mycoplasma hominis est une bactérie opportuniste qui peut être responsable d’infections du tractus urogénital, d’infections néonatales ou d’infections disséminées notamment chez les patients immunodéprimés. La membrane des mycoplasmes constitue l’interface d’interaction directe avec le milieu extérieur en raison de l’absence de paroi. Cette membrane contient de nombreuses lipoprotéines qui ont le pouvoir d’activer des cellules dendritiques humaines (hDCs), d’induire la production de cytokines et de polariser le système immunitaire adaptatif. Nous avons étudié l’interaction de M. hominis PG21 avec les hDCs en nous penchant d’une part sur la fraction du mycoplasme qui active les hDCs et d’autre part sur la réponse immunitaire innée des hDCs. Apres avoir déterminé les lipoprotéines contenues dans un extrait TX-114 de M. hominis PG21, nous avons enrichi en lipoprotéines bioactives une fraction de vésicules membranaires du mycoplasme par une double extraction utilisant deux détergents non dénaturants, le Sarkosyl puis le Triton X-114. Apres séparation par SDS-PAGE, nous avons identifié vingt lipoprotéines qui pourraient entrainer la sécrétion d’IL-23 par les hDCs, notamment la lipoprotéine MHO_4720. Un lipopeptide synthétique correspondant à la fraction N-terminale de MHO_4720 est capable de stimuler les hDCs. En analysant les variations transcriptionnelles des gènes codant pour les 48 lipoprotéines de M. hominis PG21 par qRT-PCR, nous avons également déterminé que 21 lipoprotéines sont surexprimées après 4h ou 24h de contact entre le mycoplasme et les hDCs. Enfin, la réponse cellulaire a été évaluée par PCR array et ELISA. Nous avons observé l’activation d’inflammasome(s) par la mise en évidence de la production d’IL-1β dépendant de la caspase 5. / Mycoplasma hominis is involved in urogenital tract infections, neonatal infections or disseminated infections particularly in immunocompromised patients. Mycoplasmas have no cell wall and their membrane is the main interface mediating the interaction between the mycoplasma and its environment. Lipoproteins that are anchored to the extracellular side of the plasma membrane are known to induce the maturation of human dendritic cells (hDCs), to stimulate the pro-inflammatory cytokine production by hDCs and to polarize the adaptive immune system. We studied the interaction of M. hominis PG21 with hDCs in order to assess the lipoproteins that can induce the stimulation of hDCs, to determine the lipoproteins that are regulated upon interaction of the mycoplasma with the host cell and to evaluate the innate host cell response. Using a double extraction strategy with two non-denaturing detergents, Sarkosyl then Triton X-114, and separation by SDS-PAGE, we found that 20 lipoproteins may induce the secretion of IL-23 by the hDCs, especially the MHO_4720 lipoprotein. We showed that a synthetic lipopeptide corresponding to the N-terminus part of the MHO_4720 lipoprotein can stimulate the hDCs in a dose-dependent manner. Using qRT-PCR for the evaluation of the transcriptional regulation of the 48 lipoprotein-coding genes of M. hominis PG21, we also determined that 21 lipoproteins were upregulated upon 4h and 24h of contact of M. hominis with hDCs. Finally, the hDC innate immune response was evaluated by PCR array and ELISA. We observed a caspase 5-dependent production of IL- 1β corresponding to the activation of an inflammasome.

Submitted by Carla Ferreira (carlaferreira66@gmail.com) on 2014-07-31T12:23:26Z No. of bitstreams: 2 license_rdf: 23148 bytes, checksum: 9da0b6dfac957114c6a7714714b86306 (MD5) HerminioSobrinho-2008 (1).PDF: 811492 bytes, checksum: 63a0aabcbb6458adb1051bc054066d08 (MD5) / Made available in DSpace on 2014-07-31T12:23:26Z (GMT). No. of bitstreams: 2 license_rdf: 23148 bytes, checksum: 9da0b6dfac957114c6a7714714b86306 (MD5) HerminioSobrinho-2008 (1).PDF: 811492 bytes, checksum: 63a0aabcbb6458adb1051bc054066d08 (MD5) Previous issue date: 2008 / Rheumatoid Arthritis (RA) and Systemic Lupus Erythematosus (SLE) are autoimmune diseases of unknown etiology. Some species of mycoplasmas cause arthritis in animals and humans, and their lipid-associated membrane proteins (LAMPs) and Mycoplasma arthritidis mitogen (MAM superantigen) are potent stimulators of the immune system. Thus, it has been proposed that mycoplasma can be involved in autoimmune-disease etiology. The objective of the present work was to detect antibodies to MAM and LAMPs of M. hominis and M. fermentans in the patient sera, and to characterize the profile of IgG antibodies reactivity with LAMPs in order to identify the major immunogenic mycoplasmal lipoproteins that could be involved in the etiopathogenesis of these autoimmune diseases. Serum samples were obtained from peripheral blood of female patients at the same age of healthy controls. Recombinant MAM (from M. arthrititidis), LAMPs of M. hominis PG21 and M. fermentans PG18 were used in Western blotting assays. Antibodies to MAM were detected in the patient and control sera (RA: 27.5% vs 18.8%; SLE: 21.7% vs 20.0%). At least 23 LAMPs were found in the preparations of M. hominis PG21 and of M. fermentans PG18 with molecular masses between 20 and 192 KDa. The sera of RA patients recognized a larger number of LAMPs of M. hominis PG21 and M. fermentans PG18 than the control sera (RA: 11 ± 4 vs controls: 7 ± 3, n = 35; p < 0,05). Most of the sera of RA patients presented strong reactivity with LAMPs of M. hominis PG21 (RA: 65.7% vs controls: 20%, p < 0.05). LAMPs of M. hominis PG21 with molecular masses < 49 and ? 20 KDa and LAMPs of M. fermentans PG18 < 102 and ? 58 were mainly recognized by IgG antibodies of RA patients. When comparing sera from SLE patients and controls there was detected no significant differences between the profiles of IgG reactivity. Therefore, M. hominis PG21 LAMPs (< 49 and ? 20 KDa) and M. fermentans PG18 LAMPs (< 102 and ? 58 KDa) are high immunogenic mycoplasmal antigens that can induce antibody cross reactivity with self antigen, contributing with the RA pathogenesis. / A artrite reumatóide (AR) e o lúpus eritematoso sistêmico (LES) são doenças autoimunes de etiologia desconhecida. Algumas espécies de micoplasmas causam artrite séptica em seres humanos, sendo estas bactérias fortes candidatos à etiopatogênese destas doenças. O superantígeno MAM é uma proteína secretada por Mycoplasma arthritidis, que juntamente com lipoproteínas (LAMPs) de M. hominis e M. fermentans, ativam as células do sistema imune e podem estar envolvidos na etiopatogenia da AR e do LES. O objetivo do presente trabalho foi detectar e caracterizar a resposta de anticorpos IgG contra superantígeno MAM e LAMPs de M. fermentans e M. hominis em soros de pacientes com AR ou LES, a fim de detectar as LAMPs mais imunogênicas candidatas a antígenos envolvidos na etiopatogenia destas doenças. Os pacientes com AR ou LES e os controles saudáveis eram indivíduos do sexo feminino e da mesma faixa etária. Foi usado MAM recombinante e LAMPs de M. hominis PG21 e M. fermentans PG18 extraídas com detergente Triton X-114, para avaliar o perfil de anticorpos IgG por meio da técnica de Western blotting. Anticorpos IgG anti-MAM foram detectados tanto nos soros de pacientes quanto nos dos controles (AR: 27,5% vs 18,8%; LES: 21,7% vs 20,0%). Foram detectadas pelo menos 23 LAMPs nas preparações de M. hominis PG21 e de M. fermentans PG18 com massas moleculares entre 20 e 192 KDa. Os soros de pacientes com AR reconheceram um maior número de LAMPs de M. hominis PG21 e de M. fermentans PG18 do que os soros controles (AR: 11 ± 4 vs controles: 7 ± 3, n = 35; p < 0,05). A maioria dos soros dos pacientes com AR apresentou forte reatividade com LAMPs de M. hominis PG21 (AR: 65,7% vs controles: 20%, p < 0,05). As LAMPs de M. hominis PG21 com massas moleculares <49 e ³ 20 KDa e de M. fermentans PG18 < 102 e ? 58 foram mais frequentemente reconhecidas por anticorpos IgG de soros de pacientes com AR do que por anticorpos dos soros controles. Não foram atestadas diferenças significantes entre os perfis de reatividade dos soros de pacientes com LES e controles, nem com relação ao número de LAMPs reconhecidas, nem com as diferentes faixas de massas moleculares das LAMPs. Portanto, as LAMPs de M. hominis (<49 e ³ 20 KDa) e M. fermentans (< 102 e ? 58) podem ser antígenos que induzem a produção de anticorpos que reagem cruzadamente com antígenos próprios, contribuindo para o processo da patogênese da AR.