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Journal articles on the topic "Yops. eng"
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Zhang, Yue, Galina Romanov, and James B. Bliska. "Type III Secretion System-Dependent Translocation of Ectopically Expressed Yop Effectors into Macrophages by Intracellular Yersinia pseudotuberculosis." Infection and Immunity 79, no. 11 (2011): 4322–31. http://dx.doi.org/10.1128/iai.05396-11.
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ABSTRACTYersinia pseudotuberculosisis a Gram-negative bacterial pathogen. Virulence inY. pseudotuberculosisrequires the plasmid-encoded Ysc type III secretion system (T3SS), which functions to translocate a set of effectors called Yops into infected host cells. The effectors function to antagonize phagocytosis (e.g., YopH) or to induce apoptosis (YopJ) in macrophages infected withY. pseudotuberculosis. Additionally, when antiphagocytosis is incomplete andY. pseudotuberculosisis internalized by macrophages, the bacterium can survive in phagosomes. Previous studies have shown that delivery of effectors into host cells occurs efficiently whenYersiniais extracellular. However, it is not clear whether the T3SS can be utilized by intracellularY. pseudotuberculosisto translocate Yops. This possibility was investigated here usingY. pseudotuberculosisstrains that express YopJ or YopH under the control of an inducible promoter. Bone marrow-derived murine macrophages were infected with these strains under conditions that prevented the survival of extracellular bacteria. Effector translocation was detected by measuring apoptosis or the activities of Yop-β-lactamase fusion proteins. Results showed that macrophages underwent apoptosis when YopJ expression was induced prior to phagocytosis, confirming that delivery of this effector prior to or during uptake is sufficient to cause cell death. However, macrophages also underwent apoptosis when YopJ was ectopically expressed after phagocytosis; furthermore, expression of the translocator YopB from intracellular bacteria also resulted in increased cell death. Analysis by microscopy showed that translocation of ectopically expressed YopH- or YopJ-β-lactamase fusions could be correlated with the presence of viableY. pseudotuberculosisin macrophages. Collectively, our results suggest that the Ysc T3SS ofY. pseudotuberculosiscan function within macrophage phagosomes to translocate Yops into the host cytosol.
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Ivanov, Maya I., Betty L. Noel, Ryan Rampersaud, Patricio Mena, Jorge L. Benach, and James B. Bliska. "Vaccination of Mice with a Yop Translocon Complex Elicits Antibodies That Are Protective against Infection with F1−Yersinia pestis." Infection and Immunity 76, no. 11 (2008): 5181–90. http://dx.doi.org/10.1128/iai.00189-08.
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ABSTRACT Yersinia pestis, the bacterial agent of plague, secretes several proteins important for pathogenesis or host protection. The F1 protein forms a capsule on the bacterial cell surface and is a well-characterized protective antigen but is not essential for virulence. A type III secretion system that is essential for virulence exports Yop proteins, which function as antiphagocytic or anti-inflammatory factors. Yop effectors (e.g., YopE) are delivered across the host cell plasma membrane by a translocon, composed of YopB and YopD. Complexes of YopB, YopD, and YopE (BDE) secreted by Yersinia pseudotuberculosis were purified by affinity chromatography and used as immunogens to determine if antibodies to the translocon could provide protection against Y. pestis in mice. Mice vaccinated with BDE generated high-titer immunoglobulin G antibodies specific for BDE, as shown by enzyme-linked immunosorbent assay and immunoblotting, and were protected against lethal intravenous challenge with F1− but not F1+ Y. pestis. Mice passively immunized with anti-BDE serum were protected from lethal challenge with F1− Y. pestis. The YopB protein or a complex of YopB and YopD (BD) was purified and determined by vaccination to be immunogenic in mice. Mice actively vaccinated with BD or passively vaccinated with anti-BD serum were protected against lethal challenge with F1− Y. pestis. These results indicate that anti-translocon antibodies can be used as immunotherapy to treat infections by F1− Y. pestis.
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Monack, Denise M., Joan Mecsas, Donna Bouley, and Stanley Falkow. "Yersinia-induced Apoptosis In Vivo Aids in the Establishment of a Systemic Infection of Mice." Journal of Experimental Medicine 188, no. 11 (1998): 2127–37. http://dx.doi.org/10.1084/jem.188.11.2127.
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Pathogenic Yersinia cause a systemic infection in mice that is dependent on the presence of a large plasmid encoding a number of secreted virulence proteins called Yops. We previously demonstrated that a plasmid-encoded Yop, YopJ, was essential for inducing apoptosis in cultured macrophages. Here we report that YopJ is a virulence factor in mice and is important for the establishment of a systemic infection. The oral LD50 for a yopJ mutant Yersinia pseudotuberculosis increases 64-fold compared with wild-type. Although the yopJ mutant strain is able to reach the spleen of infected mice, the mutant strain seldom reaches the same high bacterial load that is seen with wild-type Yersinia strain and begins to be cleared from infected spleens on day 4 after infection. Furthermore, when in competition with wild-type Yersinia in a mixed infection, the yopJ mutant strain is deficient for spread from the Peyer's patches to other lymphoid tissue. We also show that wild-type Yersinia induces apoptosis in vivo of Mac-1+ cells from infected mesenteric lymph nodes or spleens, as measured by quantitative flow cytometry of TUNEL (Tdt-mediated dUTP–biotin nick-end labeling)-positive cells. The levels of Mac-1+, TUNEL+ cells from tissue infected with the yopJ mutant strain were equivalent to the levels detected in cells from uninfected tissue. YopJ is necessary for the suppression of TNF-α production seen in macrophages infected with wild-type Yersinia, based on previous in vitro studies (Palmer, L.E., S. Hobbie, J.E. Galan, and J.B. Bliska. 1998. Mol. Microbiol. 27:953–965). We conclude here that YopJ plays a role in the establishment of a systemic infection by inducing apoptosis and that this is consistent with the ability to suppress the production of the proinflammatory cytokine tumor necrosis factor α.
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Lilo, Sarit, Ying Zheng, and James B. Bliska. "Caspase-1 Activation in Macrophages Infected with Yersinia pestis KIM Requires the Type III Secretion System Effector YopJ." Infection and Immunity 76, no. 9 (2008): 3911–23. http://dx.doi.org/10.1128/iai.01695-07.
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ABSTRACT Pathogenic Yersinia species utilize a type III secretion system (T3SS) to translocate effectors called Yersinia outer proteins (Yops) into infected host cells. Previous studies demonstrated a role for effector Yops in the inhibition of caspase-1-mediated cell death and secretion of interleukin-1β (IL-1β) in naïve macrophages infected with Yersinia enterocolitica. Naïve murine macrophages were infected with a panel of different Yersinia pestis and Yersinia pseudotuberculosis strains to determine whether Yops of these species inhibit caspase-1 activation. Cell death was measured by release of lactate dehydrogenase (LDH), and enzyme-linked immunosorbent assay for secreted IL-1β was used to measure caspase-1 activation. Surprisingly, isolates derived from the Y. pestis KIM strain (e.g., KIM5) displayed an unusual ability to activate caspase-1 and kill infected macrophages compared to other Y. pestis and Y. pseudotuberculosis strains tested. Secretion of IL-1β following KIM5 infection was reduced in caspase-1-deficient macrophages compared to wild-type macrophages. However, release of LDH was not reduced in caspase-1-deficient macrophages, indicating that cell death occurred independently of caspase-1. Analysis of KIM-derived strains defective for production of functional effector or translocator Yops indicated that translocation of catalytically active YopJ into macrophages was required for caspase-1 activation and cell death. Release of LDH and secretion of IL-1β were not reduced when actin polymerization was inhibited in KIM5-infected macrophages, indicating that extracellular bacteria translocating YopJ could trigger cell death and caspase-1 activation. This study uncovered a novel role for YopJ in the activation of caspase-1 in macrophages.
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Palmer, Lance E., Alessandra R. Pancetti, Steven Greenberg, and James B. Bliska. "YopJ of Yersinia spp. Is Sufficient To Cause Downregulation of Multiple Mitogen-Activated Protein Kinases in Eukaryotic Cells." Infection and Immunity 67, no. 2 (1999): 708–16. http://dx.doi.org/10.1128/iai.67.2.708-716.1999.
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ABSTRACT Pathogenic Yersinia spp. utilize a plasmid-encoded type III secretion system to deliver a set of Yop effector proteins into eukaryotic cells. Previous studies have shown that the effector YopJ is required for Yersinia to cause downregulation of the mitogen-activated protein (MAP) kinases c-Jun N-terminal kinase (JNK), p38, and extracellular signal-regulated kinase (ERK) 1 and 2 in infected macrophages. Here we demonstrate that YopJ is sufficient to cause downregulation of multiple MAP kinases in eukaryotic cells. Cellular fractionation experiments confirmed that YopJ is delivered into the cytoplasmic fraction of macrophages by the type III system. Production of YopJ in COS-1 cells by transfection significantly reduced (5- to 10-fold) activation of JNK, p38, and ERK in response to several different stimuli, including serum and tumor necrosis factor alpha. JNK activation mediated by RacV12, an activated mutant of Rac1, was also blocked by YopJ in COS-1 cells, indicating that YopJ acts downstream of this small GTPase to downregulate MAP kinase signaling. Analysis of transfected COS-1 cells by immunofluorescence microscopy revealed that YopJ is recruited from the cytoplasmic compartment to the cell periphery in response to stimuli (e.g., serum) that induce membrane ruffling. These data indicate that YopJ functions as a “MAP kinase toxin” to selectively block nuclear responses that are triggered byYersinia-host cell interaction.
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Cheng, Luisa W., Olga Kay, and Olaf Schneewind. "Regulated Secretion of YopN by the Type III Machinery of Yersinia enterocolitica." Journal of Bacteriology 183, no. 18 (2001): 5293–301. http://dx.doi.org/10.1128/jb.183.18.5293-5301.2001.
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ABSTRACT During infection, Yersinia enterocoliticaexports Yop proteins via a type III secretion pathway. Secretion is activated when the environmental concentration of calcium ions is below 100 μM (low-calcium response). Yersiniae lacking yopN (lcrE), yscB, sycN, or tyeA do not inactivate the type III pathway even when the concentration of calcium is above 100 μM (calcium-blind phenotype). Purified YscB and SycN proteins form cytoplasmic complexes that bind a region including amino acids 16 to 100 of YopN, whereas TyeA binds YopN residues 101 to 294. Translational fusion of yopN gene sequences to the 5′ end of thenpt reporter generates hybrid proteins that are transported by the type III pathway. The signal necessary and sufficient for the type III secretion of hybrid proteins is located within the first 15 codons of yopN. Expression of plasmid-borneyopN, but not ofyopN 1–294-npt, complements the calcium-blind phenotype of yopN mutants. Surprisingly,yopN mutants respond to environmental changes in calcium concentration and secrete YopN1–294-Npt in the absence but not in the presence of calcium. tyeA is required for the low-calcium regulation of YopN1–294-Npt secretion, whereassycN and yscB mutants fail to secrete YopN1–294-Npt in the presence of calcium. Experiments withyopN-npt fusions identified two other signals that regulate the secretion of YopN. yopN codons 16 to 100 prevent the entry of YopN into the type III pathway, a negative regulatory effect that is overcome by expression of yscB andsycN. The portion of YopN encoded by codons 101 to 294 prevents transport of the polypeptide across the bacterial double membrane envelope in the presence of functional tyeA. These data support a model whereby YopN transport may serve as a regulatory mechanism for the activity of the type III pathway. YscB/SycN binding facilitates the initiation of YopN into the type III pathway, whereas TyeA binding prevents transport of the polypeptide across the bacterial envelope. Changes in the environmental calcium concentration relieve the TyeA-mediated regulation, triggering YopN transport and activating the type III pathway.
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Kumar, Sanjeev, Victoria Hedrick, and Seema Mattoo. "YopT domain of the PfhB2 toxin from Pasteurella multocida: protein expression, characterization, crystallization and crystallographic analysis." Acta Crystallographica Section F Structural Biology Communications 74, no. 3 (2018): 128–34. http://dx.doi.org/10.1107/s2053230x18000857.
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Pasteurella multocida causes respiratory-tract infections in a broad range of animals, as well as opportunistic infections in humans. P. multocida secretes a multidomain toxin called PfhB2, which contains a YopT-like cysteine protease domain at its C-terminus. The YopT domain of PfhB2 contains a well conserved Cys–His–Asp catalytic triad that defines YopT family members, and shares high sequence similarity with the prototype YopT from Yersinia sp. To date, only one crystal structure of a YopT family member has been reported; however, additional structural information is needed to help characterize the varied substrate specificity and enzymatic action of this large protease family. Here, a catalytically inactive C3733S mutant of PfhB2 YopT that provides enhanced protein stability was used with the aim of gaining structural insight into the diversity within the YopT protein family. To this end, the C3733S mutant of PfhB2 YopT has been successfully cloned, overexpressed, purified and crystallized. Diffraction data sets were collected from native crystals to 3.5 Å resolution and a single-wavelength anomalous data set was collected from an iodide-derivative crystal to 3.2 Å resolution. Data pertaining to crystals belonging to space group P31, with unit-cell parameters a = 136.9, b = 136.9, c = 74.7 Å for the native crystals and a = 139.2, b = 139.2, c = 74.7 Å for the iodide-derivative crystals, are discussed.
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LEE, FRANCIS WING-LIN, and CHRIS SUM-YEE WONG. "JOB SATISFACTION OF YOUTH OUTREACH WORKERS IN HONG KONG." Hong Kong Journal of Social Work 43, no. 02 (2009): 121–44. http://dx.doi.org/10.1142/s0219246209000138.
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The promotion of job satisfaction that may lead to staff retention has always been a popular concern for human resources research. The job satisfaction and staff retention of workers in District Youth Outreaching Social Work Teams (YOTs) in Hong Kong are the themes of the present study. Through a literature review, eight facets of job satisfaction, namely Coworker Relationships, Job Complexity and Nature, Promotional Opportunity, Pay and Benefits, Work Environment, Supervision and Leadership, Role and Responsibility, and Recognition, are identified and measured among the frontline staff of the YOTs through pre-set self-administered mailed questionnaires. In relation to these facets, their intention to leave the service is also explored. The findings reveal that these workers are generally satisfied with their job (the service). At the end, some recommendations are made to promote job satisfaction and facilitate staff retention in YOTs in Hong Kong.
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Khoury, John, David Macari, Daniel Ezekwudo, Ayoda Werede, and Ishmael A. Jaiyesimi. "CLO19-040: The Role of Adjuvant Therapy in Patients With Pathological T2N0 Resected Gastric Adenocarcinoma." Journal of the National Comprehensive Cancer Network 17, no. 3.5 (2019): CLO19–040. http://dx.doi.org/10.6004/jnccn.2018.7131.
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Background: There is controversy surrounding the benefit of adjuvant therapy for patients with pT2N0, stage IB gastric adenocarcinoma following surgical resection. Methods: Patients with T2N0 gastric adenocarcinoma (tumor invasion into the muscularis propria) who underwent surgical resection with pathological evaluation of at least 15 lymph nodes were identified from the Surveillance Epidemiology and End Results Registry (SEER) database. Demographics, adjuvant therapy, and survival data were collected and analyzed using SPSS statistical software. Results: A total of 452 cases were identified between 2004 and 2014. Median age at diagnosis was 69. 60.2% of the patients were white, 27.7% Asian, 10.8% black, and 1.3% from other races. Adjuvant therapy was administered to 30.5% of the patients, of which 44.2% received chemoradiation, 48% chemotherapy only, and 7.2% radiation therapy only. After a median follow up of 39 months, the median overall survival (OS) was not reached in the group of patients who received adjuvant therapy versus 100 months in the group that did not receive adjuvant therapy (P=.005). The 5-year OS rate (5-YOS) was 77% for the adjuvant therapy group versus 62% for those who did not receive adjuvant therapy. Univariate analysis revealed that the hazard ratio for death [adjuvant therapy vs observation] was 0.54; 95% CI, 0.35 to 0.83. Adjuvant therapy showed statistically significant survival benefit in patients younger than 60 years of age (5-YOS, 95% vs 79%) and failed to show survival benefit in patients older than 60 (5-YOS, 63% vs 58%). Multivariate analysis revealed that age was associated with mortality, whereas sex, race, grade, tumor size, and number of lymph nodes examined were not associated with increased mortality. Conclusions: Adjuvant therapy provided survival benefit for pT2N0, stage IB resected gastric adenocarcinoma. Our results suggest that patients younger than 60 year of age may benefit the most from this therapy.
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Žlajpah, Leon. "Robotic yo-yo: modelling and control strategies." Robotica 24, no. 2 (2005): 211–20. http://dx.doi.org/10.1017/s0263574705002043.
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In the paper we address a problem of controlling an oscilmotion with a robot. As the object we have selected a yo-yo. First we have measured and analysed the motion of different yo-yos. We have developed a simplified model of a yo-yo which has one degree-of-freedom, and the behaviour at the end of the string is modelled as an impact. Next, we discuss the control strategy. Our results show, that for playing a yo-yo it is important to start the upward motion before the yo-yo reaches the bottom position and the acceleration has to be reversed after the bottom impact. We present two control strategies: one based on predefined hand motion pattern and and the other generating the hand motion on-line. Both allow playing the yo-yo at a selected top height. The theoretical results have been proven by experiments on a real robot system.
Dissertations / Theses on the topic "Yops. eng"
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Monnazzi, Luis Gustavo Silva. "Papel das Yops de yersinia pseudotuberculosis na modulação da resposta imune celular durante infecção experimental /." Araraquara : [s.n.], 2007. http://hdl.handle.net/11449/103335.
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Orientador: Beatriz Maria Machado de Medeiros<br>Banca: Alexandrina Sartori<br>Banca: Cleni Mara Marchocchi Machado<br>Banca: Leonilda Maria Barbosa dos Santos<br>Banca: Phileno Pinge Filho<br>Resumo: As três espécies patogênicas do gênero Yersinia, Y. pestis, Y. enterocolitica e Y. pseudotuberculosis, compartilham um tropismo pelos tecidos linfóides e um plasmídeo de 70-kb que é essencial para a virulência. O plasmídeo codifica um sistema de secreção do tipo III e proteínas efetoras chamadas Yops (Yersinia outer proteins). Este sistema de secreção é responsável por translocar as Yops para dentro das células do hospedeiro, onde elas interagem com alvos específicos e alteram as funções destas células. As Yops são capazes de modular a resposta imune do hospedeiro, permitindo à bactéria se replicar extracelularmente nos tecidos e órgãos linfóides. Embora haja muita informação sobre os mecanismos usados pela Yersinia para evadir do sistema imune inato de defesa, pouco se sabe sobre como ela afeta a resposta imune adaptativa in vivo. O objetivo deste trabalho foi analisar a influência das Yops E, H e M, translocadas pela Y. pseudotuberculosis, na colonização e persistência da bactéria no baço e fígado dos animais infectados, nas quantidades de LT-CD4 e LT-CD8 durante a infecção e na produção das principais citocinas Th1 e Th2 por estas subpopulações de linfócitos. Além disso, foi verificado o papel destas Yops sobre a ativação do fator nuclear κB (NF-κB) e sobre a atividade citotóxica dos LT-CD8. Para isso, camundongos BALB/c fêmeas foram infectados intravenosamente com a amostra selvagem de Y. pseudotuberculosis (WT), ou com amostras mutantes incapazes de secretar as Yops E, H e M (YopE-, YopH- e YopM-), ou ainda com a amostra curada do plasmídeo de virulência (YpIII). No 5°, 7°, 14° e 21° dia pós-infecção (pi), os animais foram sacrificados e as células esplênicas foram obtidas de camundongos infectados e de camundongos não infectados (grupo controle). Os níveis de colonização no baço e no fígado foram determinados por... (Resumo completo, clicar acesso eletrônico abaixo)<br>Abstract: The three pathogenic species of the genus Yersinia, Y. pestis, Y. enterocolitica and Y. pseudotuberculosis, share a tropism for lymphoid tissues and a 70-kb plasmid essential for virulence. The plasmid encodes a type III secretion system and effector proteins called Yops (Yersinia outer proteins). This secretion system is responsible for translocating the Yops into the host cells, where they interact with specific host targets and alter the functions of these cells. Yops are able to modulate the host immune defenses allowing the bacteria to replicate extracellularly in lymphoid tissues and organs. Although there is ample information on the mechanisms used by Yersinia to evade the innate immune system, very little is known about how it affects the adaptive immune response in vivo. The aim of this research was to analyze the influence of translocated Yops E, H and M of Y. pseudotuberculosis on the colonization and persistence of the bacterium in the spleen and liver of infected animals, on the quantities of CD4 and CD8 T cells during the infection and on the production of the main Th1 and Th2 cytokines by these lymphocyte subpopulations. In addition, it was verified the role of these same Yops on the activation of nuclear factor κB (NF- κB) and on the CD8 T cells cytotoxic activity. To this end, female BALB/c mice were infected intravenously with the wild type Y. pseudotuberculosis (WT), or with the mutant strains unable to secrete the Yops E, H and M (YopE-, YopH- and YopM-) or with the plasmid-cured strain (YpIII). On the 5th, 7th, 14th and 21st days post-infection (pi), the animals were sacrificed and the spleen cells were isolated from infected and uninfected mice (control group). The levels of colonization in the spleen and liver were determined by counting the number of colony-forming units. Both the phenotypic analysis of lymphocytes and the intracellular... (Complete abstract click electronic access below)<br>Doutor
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Maia, José Mário Lourenço. "Influência das proteínas "Yops" de Yersinia pseudotuberculosis na resposta imune humoral murina /." Araraquara : [s.n.], 2006. http://hdl.handle.net/11449/99651.
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Orientador: Beatriz Maria Machado de Medeiros<br>Banca: Dagmar Ruth Stach Machado<br>Banca: Alexandrina Sartori<br>Resumo: As proteínas Yops. formam uma família de proteínas secretadas por Yersinia spp que incluem efetores intracelulares (seis efetores foram identificados: YopE, YopH, YopM, YpkA/YopO, YopJ/YopP e YopT) e vários componentes do aparato de secreção-translocação que são liberado pela bactéria sob quelação de Ca2+. As .Yops. efetoras têm sido relacionadas a uma série de propriedades de virulência, incluindo resistência à fagocitose, citotoxicidade e desfosforilação de proteínas do hospedeiro. Porém, a interação das .Yops. de Yersinia com a resposta imune específica do hospedeiro não está bem esclarecida. O objetivo deste estudo foi investigar o papel imunomodulador das "Yops" secretadas por amostras de Yersinia pseudotuberculosis sobre a produção de anticorpos e autoanticorpos por linfócitos B. Para tanto camundongos foram infectados com uma amostra selvagem de Y. pseudotuberculosis (YpIII) e com amostras mutantes, defectivas na secreção de determinadas .Yops. efetoras (YopH, YopE, YopM, YpkA e YopJ). Foram obtidas células esplênicas destes animais, e as células secretoras de imunoglobulinas inespecíficas e específicas (anti-Yersinia e anti-.Yops.) foram quantificadas através do teste ELISPOT. A presença de anticorpos específicos anti-Yersinia e anti-.Yops. no soro dos animais infectados foi analisada através do teste ELISA. A presença de auto-anticorpos séricos foi analisada através do teste DOT-BLOT. Não se observou nenhuma diferença entre o número de células secretoras de imunoglobulinas (Igs) inespecíficas dos animais inoculados com a amostra selvagem, YpIIIpIB102 (wt), em relação aos controles. Já a amostra YpIII pIB522, embora defectiva na secreção de YopE, provocou uma redução dos linfócitos B secretores de IgG2a, IgM e IgA. A única ativação observada ocorreu para o isotipo IgG2a (aumento de 1,7 vezes)... (Resumo completo, clicar acesso eletrônico abaixo)<br>Abstract: The "Yops" proteins form a protein family secreted by Yersinia spp that includes intracellular effectors (six effectors had been identified: YopE , YopH, YopM, YpkA/YopO, YopJ/YopP and YopT) and some components of the secretion-translocation apparatus that are released by the bacteria under Ca2+ quelation. The "Yops" effectors have been related to a series of virulence properties, including resistance to phagocytosis, citotoxicity and desfosforilation of host proteins. However, the interaction of the Yersinia "Yops" with the host specific immune response is not well defined. The objective of this study was to investigate the immunomodulatory role of the "Yops" secreted by strains of Yersinia pseudotuberculosis on the production of antibodies and autoantibodies by splenic B lymphocytes. To this end, mice were infected with wild-type Y. pseudotuberculosis (YpIII) or with mutant strains, unable to secrete specific "Yops" (YopH, YopE, YopM, YpkA and YopJ). Spleen cells were obtained, and the cells secreting nonspecific and specific immunoglobulins (anti-Yersinia and anti-"Yops") was quantified by the ELISPOT technique. The presence of anti-Yersinia and anti- .Yops. specific antibodies in infected mice serum was investigated by ELISA and the presence of autoantibodies by DOT-BLOT assay. It was not observed neither difference between the number of nonspecific Igs-secreting cells of the animals infected with YpIIIpIB102 (wt) in relation to the controls. The strain YpIII pIB522, although defective in YopE secretion, provoked a reduction in the B lymphocytes secreting IgG2a, IgM and IgA. The unique activation observed was that of IgG2a isotype (an increase of 1.7-fold) on the 7th day post infection. The YopH- strain, YpIII pIB29, provoked an increase in the number of IgG1-, IgG2a- and IgG3- secreting cells (between 1.4 to 2.4-fold), on the 7th and 14th days post infection... (Complete abstract, click electronic address below)<br>Mestre