Avaliação da resposta imunológica da mucosa intestinal de frangos de corte desafiados com diferentes sorovares de Salmonella / Evaluation of immune response of the intestinal mucosa in broilers challenged with different Salmonella serovars

Objetivou-se com o presente estudo comparar o efeito de diferentes sorovares de Salmonella na resposta imune local da mucosa do intestino de frangos de corte. Aos sete dias de idade, as aves foram desafiadas com os sorovares S. Enteritidis, S. Typhimurium, S. Senftenberg, S. Mbandaka e S. Minnesota. Foi observado que todos os sorovares testados foram capazes de colonizar o intestino das aves sendo possível o isolamento de Salmonella em suabes de cloaca, 48 h após inoculação. De maneira geral, as aves do grupo controle negativo, que não foram desafiados apresentaram quantidade significativamente menor de células imunológicas na mucosa intestinal do que as aves desafiadas. Porém, verificou-se que os sorovares de Salmonella, utilizados neste estudo, apresentaram diferentes efeitos sobre a dinâmica celular da mucosa do íleo e ceco e afetaram de modo diferente o ganho de peso e ganho médio diário das aves demonstrando distintos graus de patogenicidade. Os sorovares Enteritidis e Typhimurium apresentaram um efeito mais intenso tanto no desempenho quanto na mobilização de células imunológicas na mucosa intestinal de frangos de corte.

The study was designed to compare the effect of different Salmonella serovars in immune response across the count of CD8+ cells, CD4+ cells, goblet cells and macrophages in the gut mucosa of broilers. During the experimental inoculation at 7 day-old were used Salmonella enterica subspecies enterica sorovars Enteritidis, Typhimurium, Senftenberg, Mbandaka and Minnesota. It was observed that all serovars tested were capable of contaminating the poultry being possible counts of Salmonella in cloacal swabs, 48 h after inoculation and into the crop and cecum, at 14 and 20 day-old. Serovars tested had different effects on broiler performance assessed at 20 days. In the mucosa of the ileum and cecum of broilers, it was observed that some of the serotypes increased CD8 + cells, CD4 + cells, goblet cells and macrophages compared to the negative control group both at 14 and at 20 day-old. S. Enteritidis and S. Typhimurium are the serovars that showed the more intense effect in live performance and in the immune system of birds showing pathogenic characteristic; generally the broilers of the negative control showed significantly less immune cells on the intestinal mucosa than broilers inoculated experimentally. However, it was found that the Salmonella serovars used in this study had different effects on the cellular dynamics of the mucosa of the ileum and cecum and differently affect weight gain and average daily gain of poultry showing different levels of pathogenicity.

Enhancing mucosal immunity in mice by recombinant adenovirus expressing major epitopes of porcine circovirus-2 capsid protein delivered with cytosine-phosphate-guanosine oligodeoxynucleotides

A recombinant replication-defective adenovirus expressing the major epitopes of porcine circovirus-2 (PCV-2) capsid protein (rAd/Cap/518) was previously constructed and shown to induce mucosal immunity in mice following intranasal delivery. In the present study, immune responses induced by intranasal immunization with a combination of rAd/Cap/518 and cytosine-phosphate-guanosine oligodeoxynucleotides (CpG ODN) were evaluated in mice. The levels of PCV-2-specific IgG in serum and IgA in saliva, lung, and intestinal fluids were significantly higher in the group immunized with rAd/Cap/518 and CpG ODN than animals immunized with rAd/Cap/518 alone. The frequencies of IL-2-secreting CD4+ T cells and IFN-gamma-producing CD8+ T cells were significantly higher in the combined immunization group than mice immunized with rAd/Cap/518 alone. The frequencies of CD3+, CD3+CD4+CD8-, and CD3+CD4-CD8+ T cells in the combined immunization group were similar to that treated with CpG ODN alone, but significantly higher than mice that did not receive CpG ODN. PCV-2 load after challenge in the combined immunization group was significantly lower than that in the phosphate-buffered saline placebo group and approximately 7-fold lower in the group treated with CpG ODN alone. These results indicate that rAd/Cap/518 combined with CpG ODN can enhance systemic and local mucosal immunity in mice, and represent a promising synergetic mucosal vaccine against PCV-2.

Recognition of enteroinvasive Escherichia coli and Shigella flexneri by dendritic cells: distinct dendritic cell activation states

The innate and adaptive immune responses of dendritic cells (DCs) to enteroinvasive Escherichia coli (EIEC) infection were compared with DC responses to Shigella flexneri infection. EIEC triggered DCs to produce interleukin (IL)-10, IL-12 and tumour necrosis factor (TNF)-α, whereas S. flexneri induced only the production of TNF-α. Unlike S. flexneri, EIEC strongly increased the expression of toll like receptor (TLR)-4 and TLR-5 in DCs and diminished the expression of co-stimulatory molecules that may cooperate to inhibit CD4+ T-lymphocyte proliferation. The inflammation elicited by EIEC seems to be related to innate immunity both because of the aforementioned results and because only EIEC were able to stimulate DC transmigration across polarised Caco-2 cell monolayers, a mechanism likely to be associated with the secretion of CC chemokine ligands (CCL)20 and TNF-α. Understanding intestinal DC biology is critical to unravelling the infection strategies of EIEC and may aid in the design of treatments for infectious diseases.

Caracterização da resposta imune celular de pacientes portadores da esquistossomose mansônica residentes em áreas endêmicas para doença / Characterization of the cellular immune response of schistosomiasis patients living in areas endemic for disease

Neste estudo foram avaliadas as principais alterações hematológicas e imunofenotípicasem pacientes portadores da fase crônica da esquistossomose (INF), subcategorizadospor cargas parasitárias distintas, apresentando menos de 100 ovos por grama de fezes(<100) e mais de 100 ovos por grama de fezes (>100) e indivíduos negativos para ovosresidentes (CA) ou não (CT) em áreas endêmicas para a doença. Amostras de fezes esangue periférico foram coletadas para realização de exame parasitológico pelo métodode Kato-Katz e hemograma, respectivamente. Logo após, foi realizado a avaliação doperfil imunofenotípico ex vivo dos leucócitos circulantes e a produção de citocinas emculturas de células mononucleares do sangue periférico, após estimulação antigênica invitro por 12 horas na ausência ou presença de antígenos solúveis do ovo (SEA), doverme adulto (SWAP) e proteínas recombinantes (Sm22.6 e Sm29) do Schistosomamansoni. Os resultados mostraram aumento no número absoluto de eosinófilos nosgrupos INF e >100. Em relação ao perfil imunofenotípico, foi observado aumento daexpressão dos receptores do Tipo Toll-2, CD80, CD86 e CD54 em monócitos dosgrupos CA, INF, e >100 em relação ao grupo CT. Foi observado também aumento doreceptor CD18 em linfócitos T CD4+ dos grupos CA e <100 em relação ao grupo CT,diminuição do CD18 no grupo >100 em relação ao grupo <100 e aumento da expressãodo CD18 no grupo <100 em relação ao grupo CA. Em linfócitos T CD8+ foi observadoaumento na expressão do receptor do tipo Toll-2 nos grupos INF, <100 e >100 emrelação ao grupo CT, aumento do CD18 nos grupos <100 e CA em relação ao grupo CTe diminuição do CD18 no grupo >100 em relação ao grupo <100. Em linfócitos B, foiobservado aumento da expressão do receptor CD80 e CD86 no grupo <100 em relaçãoao CT e aumento na expressão do CD86 no grupo CA em relação ao grupo CT. Aanálise após estimulação antigênica revelou, em monócitos, aumento da síntese de TGF-nos grupos INF e >100 estimulados com Sm22.6 e SEA em relação ao CA, reduçãona síntese de IL-10 e IL-12 no grupo INF em relação ao grupo CA estimulado comSm22.6 e redução na síntese de IL-1nos grupos CAINF, <100 e >100estimuladoscom Sm22.6 e SEA em relação ao meio. Houve também, redução de expressão de IL-5no grupo <100 em relação ao CA estimulado com Sm22.6, aumento na síntese de IFN- nos grupo INF e >100 estimulados com SEA em relação ao meio e aumento nasíntese de F-e IL-10 nos grupo INF e >100 estimulados com Sm22.6 e SEAem relação ao grupo CA em linfócitos T CD4+. Além disso, houve aumento da síntese deIL-12 e TNF-no grupo INF em relação ao CA estimulado com SEA, redução de IL-8no grupo >100 em relação ao grupo <100 estimulados com SEA, SWAP e Sm22.6 eredução de síntese de IL-5 no grupo INF estimulado com SWAP em relação ao CA emlinfócitos T CD8+. Após a realização desse trabalho, pode-se concluir que indivíduosportadores da fase crônica e residentes em área endêmica para a doença apresentamforte expressão de moléculas co-estimuladoras, de adesão e de ativação celular emmonócitos, linfócitos B, linfócitos T CD4+ e CD8+ do sangue periférico, sugerindo queestes indivíduos possuam intensa atividade das células envolvidas na resposta imunecontra a infecção pelo S. mansoni. Além disso, de uma maneira geral, os indivíduosinfectados apresentaram, após estimulação antigênica com antígenos recombinantes,redução na síntese de citocinas pró inflamatórias e aumento da síntese de citocinasreguladoras tanto para monócitos quanto para linfócitos. Isto mostra uma enormecapacidade que esses antígenos possuem em induzir uma modulação da resposta imunerelacionada à resistência a infecção e a uma menor gravidade da doença. Acategorização da população estudada, segundo intensidades de infecção distintas,definiu a contribuição dessa variável para os mecanismos de resistência esusceptibilidade durante a infecção esquistossomótica.

Caracterização da resposta imune celular de pacientes portadores da esquistossomose mansônica residentes em áreas endêmicas para doença

Neste estudo foram avaliadas as principais alterações hematológicas e imunofenotípicasem pacientes portadores da fase crônica da esquistossomose (INF), subcategorizadospor cargas parasitárias distintas, apresentando menos de 100 ovos por grama de fezes(100) e indivíduos negativos para ovosresidentes (CA) ou não (CT) em áreas endêmicas para a doença. Amostras de fezes esangue periférico foram coletadas para realização de exame parasitológico pelo métodode Kato-Katz e hemograma, respectivamente. Logo após, foi realizado a avaliação doperfil imunofenotípico ex vivo dos leucócitos circulantes e a produção de citocinas emculturas de células mononucleares do sangue periférico, após estimulação antigênica invitro por 12 horas na ausência ou presença de antígenos solúveis do ovo (SEA), doverme adulto (SWAP) e proteínas recombinantes (Sm22.6 e Sm29) do Schistosomamansoni. Os resultados mostraram aumento no número absoluto de eosinófilos nosgrupos INF e >100

Em relação ao perfil imunofenotípico, foi observado aumento daexpressão dos receptores do Tipo Toll-2, CD80, CD86 e CD54 em monócitos dosgrupos CA, INF, e >100 em relação ao grupo CT. Foi observado também aumento doreceptor CD18 em linfócitos T CD4+ dos grupos CA e 100 em relação ao grupo 100 emrelação ao grupo CT, aumento do CD18 nos grupos 100 em relação ao grupo 100 estimulados com Sm22.6 e SEA em relação ao CA, reduçãona síntese de IL-10 e IL-12 no grupo INF em relação ao grupo CA estimulado comSm22.6 e redução na síntese de IL-1nos grupos CAINF, 100estimuladoscom Sm22.6 e SEA em relação ao meio. Houve também, redução de expressão de IL-5no grupo 100 estimulados com SEA em relação ao meio e aumento nasíntese de F-e IL-10 nos grupo INF e >100 estimulados com Sm22.6 e SEAem

relação ao grupo CA em linfócitos T CD4+. Além disso, houve aumento da síntese deIL-12 e TNF-no grupo INF em relação ao CA estimulado com SEA, redução de IL-8no grupo >100 em relação ao grupo <100 estimulados com SEA, SWAP e Sm22.6 eredução de síntese de IL-5 no grupo INF estimulado com SWAP em relação ao CA emlinfócitos T CD8+. Após a realização desse trabalho, pode-se concluir que indivíduosportadores da fase crônica e residentes em área endêmica para a doença apresentamforte expressão de moléculas co-estimuladoras, de adesão e de ativação celular emmonócitos, linfócitos B, linfócitos T CD4+ e CD8+ do sangue periférico, sugerindo queestes indivíduos possuam intensa atividade das células envolvidas na resposta imunecontra a infecção pelo S. mansoni. Além disso, de uma maneira geral, os indivíduosinfectados apresentaram, após estimulação antigênica com antígenos recombinantes,redução na síntese de citocinas pró inflamatórias e aumento da síntese de citocinasreguladoras tanto para monócitos quanto para linfócitos. Isto mostra uma enormecapacidade que esses antígenos possuem em induzir uma modulação da resposta imunerelacionada à resistência a infecção e a uma menor gravidade da doença. Acategorização da população estudada, segundo intensidades de infecção distintas,definiu a contribuição dessa variável para os mecanismos de resistência esusceptibilidade durante a infecção esquistossomótica

Ontogenia da resposta imune de mucosas e colonização por micro-organismos orais / Ontogeny of mucosal immune response and colonization by oral microorganisms

O objetivo desta revisão é fornecer informações sobre o desenvolvimento da resposta imune de mucosas, em especial da IgA secretora (IgAS) nas salivas de crianças (pré-termo ou a termo) e sua ação frente aos micro-organismos orais. A análise do sistema imune de mucosas representa um caminho interessante para o entendimento da colonização microbiana nos primeiros meses de vida, em especial a resposta de IgAS presente na saliva, pois esta representa a primeira linha de defesa. A maioria dos estudos sobre a resposta imune específica a micro-organismos orais residentes envolve o Streptococcus mutans, que é o principal agente etiológico da cárie dentária e vem contribuindo para melhor conhecimento e prevenção desta doença que ainda representa um enorme desafio por seu caráter multifatorial e tratamento difícil. Assim, o entendimento precoce dos inúmeros fatores que podem influenciar o desenvolvimento imunológico de mucosa e o padrão de resposta à diversidade microbiana adquirida após o nascimento podem fornecer importantes informações para a elaboração de estratégias de controle de infecção.

Reduction of the amount of intestinal secretory IgA in fulminant hepatic failure

Intestinal barrier dysfunction plays an important role in spontaneous bacterial peritonitis. In the present study, changes in the intestinal barrier with regard to levels of secretory immunoglobulin A (SIgA) and its components were studied in fulminant hepatic failure (FHF). Immunohistochemistry and double immunofluorescent staining were used to detect intestinal IgA, the secretory component (SC) and SIgA in patients with FHF (20 patients) and in an animal model with FHF (120 mice). Real-time PCR was used to detect intestinal SC mRNA in the animal model with FHF. Intestinal SIgA, IgA, and SC staining in patients with FHF was significantly weaker than in the normal control group (30 patients). Intestinal IgA and SC staining was significantly weaker in the animal model with FHF than in the control groups (normal saline: 30 mice; lipopolysaccharide: 50 mice; D-galactosamine: 50 mice; FHF: 120 mice). SC mRNA of the animal model with FHF at 2, 6, and 9 h after injection was 0.4 ± 0.02, 0.3 ± 0.01, 0.09 ± 0.01, respectively. SC mRNA of the animal model with FHF was significantly decreased compared to the normal saline group (1.0 ± 0.02) and lipopolysaccharide group (0.89 ± 0.01). The decrease in intestinal SIgA and SC induced failure of the intestinal immunologic barrier and the attenuation of gut immunity in the presence of FHF.

Cholera toxin – A foe & a friend.

After De’s pivotal demonstration in 1959 of a diarrhoeogenic exo-enterotoxin in cell-free culture filtrates from Vibrio cholerae (of classical biotype), much insight has been gained about cholera toxin (CT), which is arguably now the best known of all microbial toxins. The subunit structure and function of CT, its receptor (the GM1 ganglioside), and its effects on the cyclic AMP system and on intestinal secretion were defined in the 1970s, and the essential aspects of the genetic organization in the 1980s. Recent findings have generated additional perspectives. The 3D-crystal structure of CT has been established, the CT-encoding operon has been shown to be carried by a non-lytic bacteriophage, and in depth knowledge has been gained on how the bacterium controls CT gene expression in response to cell density and various environmental signals. The mode of entry into target cells and the intracellular transport of CT are becoming clearer. CT has become the prototype enterotoxin and a widely used tool for elucidating important aspects of cell biology and physiology, e.g., cell membrane receptors, the cyclic AMP system, G proteins, as well as normal and pathological ion transport mechanisms. In immunology, CT has emerged as a potent, widely used experimental adjuvant, and the strong oral-mucosal immunogenicity of the non-toxic B-subunit (CTB) has led to the use of CTB as a protective antigen together with killed vibrios in a widely licensed oral cholera vaccine. CTB has also been shown to promote immunological tolerance against certain types of mucosally co-administered antigens, preferably tissue antigens linked to the CTB molecule; this has stimulated research and development to use CTB in this context for treatment of autoimmune and allergic diseases. In summary, in the 50 years after De’s discovery of CT, this molecule has emerged from being the cholera patient’s “foe” to also becoming a highly useful scientist’s “friend”.

The effects of nitric oxide on the immune response during giardiasis

Nitric oxide (NO) is a free radical synthesized from L-arginine by different isoforms NO-synthases. NO possesses multiple and complex biological functions. NO is an important mediator of homeostasis, and changes in its generation or actions can contribute or not to pathological states. The knowledge of effects of NO has been not only important to our understanding of immune response, but also to new tools for research and treatment of various diseases. Knowing the importance of NO as inflammatory mediator in diverse infectious diseases, we decided to develop a revision that shows the participation/effect of this mediator in immune response induced against Giardia spp. Several studies already demonstrated the participation of NO with microbicidal and microbiostatic activity in giardiasis. On the other hand, some works report that Giardia spp. inhibit NO production by consuming the intermediate metabolite arginine. In fact, studies in vitro showed that G. lamblia infection of human intestinal epithelial cells had reduced NO production. This occurs due to limited offer of the crucial substrate arginine (essential aminoacid for NO production), consequently reducing NO production. Therefore, the balance between giardial arginine consumption and epithelial NO production could contribute to the variability of the duration and severity of infections by this ubiquitous parasite.

Caracterización de la respuesta inmunitaria de bovinos infectados con Mycobacterium bovis en condiciones de campo en el municipio Colón estado Zulia Venezuela / Characterization of the immune response of bovines with Mycobacterim bovis field infection in an area with high incidence of bovine tuberculosis in Venezuela

La tuberculosis bovina es una enfermedad crónica, zoonótica, infecciosa y contagiosa teniendo como agente causal al Mycobacterium bovis inductor de una respuesta inmunitaria diversa. Esta abarca, desde una respuesta celular capaz de controlar la infección, pasando por una potente, más no eficiente respuesta humoral, hasta un estado de no respuesta o anergia, coadyuvante de la diseminación de la micobacteria. En este estudio se evaluaron animales seleccionados por el Instituto Nacional de Salud Agrícola Integral (INSAI), como reactores a la prueba simple de la Tuberculina en una finca con antecedentes de tuberculosis por más de 20 años. A estos animales se le aplicaron las siguientes pruebas: Comparativa del PPD (PPD-B y PPD-A), prueba de Interferón Gamma (INFy) y un ensayo inmunoenzimático para TBC (ELISA-TBC), seguidamente se realizó la inspección post morten en el frigorífico donde se evaluaron y clasificaron las lesiones macroscópicas compatibles con tuberculosis. Los tejidos seleccionados fueron utilizados para estudios bacteriológicos, extracción de ADN y posterior amplificación secuencia específica con cebadores y oligonucleótidos IS6110 específicos para el complejo M. tuberculosis, aplicando la prueba de Reacción en Cadena de la Polimerasa (PCR-SSP) para la identificación definitiva del patógeno. El resultado de estas pruebas permitió observar diferentes patrones de respuesta inmunitaria: celular (PPD+/IFN-y-, PPD+/IFNy+, PPD-/IFNy+), mixto (PPD+ o IFN-y+/ELISA-TBC+) y humoral (ELISA-TBC+). Igualmente se detectaron animales anérgicos, negativos a todas las pruebas inmunológicas, positivos en bacteriología y PCR-SSP. Se pudo establecer la progresión de la enfermedad a partir de la severidad de las lesiones y la edad de los animales. Estos patrones pueden aparecer al inicio de la infección o ser el resultado de la progresión crónica de la enfermedad. Estas diferentes respuestas inmunitarias pueden explicar la permanencia de la infección...

The bovine tuberculosis is a chronic, zoonótic infectious disease and contagious having as causal agent to the Mycobacterium bovis inductive of a diverse immune response. This sandal, from an answer cellular, able to control the infection, happening through powerful, but a nonefficient one, humoral response to a state of not response or anergia, facilitating the dissemination of mycobacteria. In this study animals selected by the Venezuelan National Institute of Integral Agricultural Health (INSAI), like reactors to the simple test of the Tuberculina in a property with antecedents of tuberculosis by but of 20 years. To these animals the following tests were applied: Comparative of the tuberculina (PPD-B and PPD-A), test for Gamma Interferon (INF-y) and a Immun-enzimatic Test for TBC (ELISA-TBC), next was made the inspection post morten in the refrigerator where the compatible macrocospic injuries with tuberculosis were evaluated and classified. The selected weaves were used for bacteriological studies, DNA extraction and later amplification specific sequence with specific boots IS6110 for tuberculoso complex M., applying the test of Chain Reaction of Polimerasa (PCR-SSP) for the definitive identification of the pathogen. The result of these tests allowed to observe different patterns from immune response: cellular (PPD+, PPD+ - INF-y + or INF-y +), mixed (PPD+ and/or INF-y, ELISA-TBC+) and humoral (ELISA-TBC). Also anérgics animals detected themselves, negatives to all the immunological tests, positive in bacteriology and PCR-SSP. It was possible to be established the progression of the disease from the severity of the injuries and the age of the animals. These different immune responses may explain the persistence of infection in farm notwithstanding the implementation of the resolution of official control and eradication of Bovine Tuberculosis in the region.

Secretory immunoglobulin A: a protective factor in the genital mucosa

The genital mechanisms of defense are not well understood and are therefore ignored during therapy. This fact results in a great number of cases of treatment failure. The mucosa is an important protective factor of the genital female system, through self-defense mechanisms, and secretor antibodies (immunoglobulin A). The lymphoid tissue exerts protective anti-inflammatory activity, besides inhibiting microorganism adherence, neutralizes viruses and toxins and stabilizes the mucosal flora. Although certain microorganisms, such as viruses and fungus, are controlled by cellular immunity, secretory IgA can also exert an important role in the control of these agents.

Good bug, bad bug: in the case of enteric inflammatory disease does the epithelium decide?

Many studies demonstrate that intestinal inflammation is either initiated or exaggerated by a component of the normal microbiota, most likely commensal bacteria or products derived from these organisms. We review the nature of human inflammatory bowel disease, the evidence for the involvement of the normal bacterial flora in these disorders and the relevance of maintaining the integrity of the epithelial barrier. Moreover, we, and others, have shown abnormal mitochondria structure in tissue resections from patients with inflammatory bowel disease and tissues from rodents that demonstrated psychological stress-induced increases in epithelial permeability. Thus, we also consider the possibility that a defect in epithelial mitochondrial function would predispose an individual to respond to their commensal bacteria flora - no longer considering them as a beneficial passive inhabitant, but rather perceiving them as a threatening and pro-inflammatory stimulus. In support of this postulate, we discuss our recent findings from an in vitro model showing that the human colon-derived T84 cell line exposed to the metabolic stressor, dinitrophenol, and the non-pathogenic, non-invasive, Escherichia coli (strain HB101) display a loss of barrier function, increased signal transduction and increased production of the chemokine, interleukin 8.

Spontaneous inflammatory pelvic disease in adult non-castrated female rats treated with estrogen

The adaptive immune response of the genital tract is under the control of sexual steroids; however, the influence of sex hormones on innate immune mechanisms of the genital mucosa are only beginning to be understood. We found that long-term estrogen treatment increases the risk for inflammatory pelvic diseases in adult non-castrated female rats. Female rats (110 g to 130 g) received estrogen (10 rats; 17-beta estradiol, 50 mg pellet; 10 rats: subcutaneous weekly injection of estradiol valerate 0.166 mg/kg). Ten rats received a pellet of 17-beta estradiol and were treated with amoxicillin, 50 mg/kg after the 90th day of exposure to estrogen. Three control groups of ten rats were also used. The estrogen-treated rats developed an inflammatory pelvic disease, with abscess formation after the third month of hormonal treatment. All the surviving animals were killed after six months of hormonal exposure. Among 15 survivors of the two groups that received estrogen 13 animals presented tuboovarian abscesses. Among eight survivors of the group treated with amoxicillin, six had tuboovarian abscesses. None of the 30 control rats presented macro or microscopic signs of inflammatory disease in the uterus, tubes or ovaries. We conclude that estrogen impairs the defense mechanisms of the genital tract of non-castrated female rats, enhancing bacterial growth in the vagina and ascending infection to the uterus, tubes and ovaries.

A predictive model for the level of sIgA based on IgG levels following the oral administration of antigens expressed in Sacchromyces cerevisiae

Oral vaccination may be the most efficient way of inducing an immune response at the remote mucosal site through the common mucosal immune network. Antigenspecific secretory IgA (sIgA) is the major immunoglobulin type generally detected in the secretions of experimental animals following an effective oral immunization. Actinobacillus pleuropneumoniae causing disease in the lung of pig initially interacts, colonizes, and infects the host tissues at the mucosal surface of the respiratory tract. Also, importantly for A. pleuropneumoniae protection, the quantity of sIgA in the lung had merits associated with the mucosal immunity. However, there is no simple method to monitor the level of sIgA as an indicator for the induction of local immune responses by an oral vaccination in the target tissue. Therefore, the relationship between sIgA and IgG was analyzed to evaluate the induction of local immune responses by an oral immunization with Saccharomyces cerevisiae expressing the apxIA and apxIIA genes of A. pleuropneumoniae in this study. The correlation coefficient of determination (r2 x 100) for paired samples in both vaccinated and control groups showed a significant positive-relationship between IgG in sera and sIgA in the lung or intestine. These results indicated that IgG antibody titers in sera could be useful to indirectly predict local immune response, and sIgA, in the lung or intestine to evaluate the efficacy of an oral vaccination.

Role of mast cells in gastrointestinal mucosal defense

The purpose of this review, based on studies from our laboratory as well as from others, is to summarize salient features of mast cell immunobiology and to describe their associations with gastrointestinal mucosal defense. Gastrointestinal mast cells are involved in many pathologic effects, such as food hypersensitivity. On the other hand, they also play a protective role in defense against parasitic and microbial infections. Thus, they have both positive and negative effects, but presently the mechanisms that control the balance of these various effects are poorly known. It has been suggested that stabilization of mast cells may be a key mechanism to protect the gastrointestinal tract from injury. Few molecules are known to possess both mast cell stabilizing and gastrointestinal cytoprotective activity. These include zinc compounds, sodium cromoglycate, FPL 52694, ketotifen, aloe vera, certain flavonoids such as quercetin, some sulfated proteoglycans such as chondroitin sulfate and dehydroleucodine. Dehydroleucodine, a sesquiterpene lactone isolated from Artemisia douglasiana Besser, exhibits anti-inflammatory and gastrointestinal cytoprotective action. The lactone stimulates mucus production, and inhibits histamine and serotonin release from intestinal mast cells. The lactone could act as a selective mast cell stabilizer by releasing cytoprotective factors and inhibiting pro-inflammatory mast cell mediators.

Imunogenicidade do vírus vaccinia recombinante modificado com o gene do Antígeno Cárcino-Embrionário (CEA) humano em modelo experimental de adenocarcinoma de cólon / Immunogenicity of recombinant modified vaccinia virus with the gene-Carcino Embryonic Antigen (CEA) in an experimental model of human colon adenocarcinoma

Os adenocarcinomas do trato gastrointestinal desenvolvem inicialmente a partir do epitélio superficial, e em mais de 90% dos casos expressam o CEA. Existe compartimentalização e alguma independência entre o sistema imunológico mucoso e sistêmico com tráfego assimétrico de células entre eles. Um melhor conhecimento da imunologia dos tumores tem gerado o desenvolvimento de várias abordagens de vacinas direcionadas contra antígenos tumorais específicos. O vírus vaccinia está entre os mais potentes para a indução de resposta protetora em animais contra infecções virais e câncer. Os animais foram imunizados intra-retal ou intravenoso com 10 milhões de partículas do vírus Vaccinia recombinante com o CEA a cada 15 dias totalizando 3 doses. O grupo controle recebeu a mesma imunização com o mesmo vetor porém, não transduzido com o CEA. Metade dos animais em cada grupo foi sacrificada 7 dias após a última imunização para se avaliar a indução de resposta imunológica contra o CEA no baço (sistêmica) e nas placas de Peyer intestinais (mucosa). A imunização intra-retal com o rVac-CEA se mostrou factível com índice de resposta maior que 50%. A citotoxicidade contra o CEA após imunização intra-retal bem como mucosa após imunização sistêmica foi medida no baço e placas de Peyer. Ambas as vias de imunização induziram proteção contra tumores CEA+mas a via EV foi mais eficiente para tumores implantados no subcutâneo. O camundongo Apc/CEA é um relevante modelo animal para o estudo do desenvolvimento espontâneo do câncer de cólon da fase de displasia ao adenocarcinoma invasivo. O CEA humano é superexpressado nos tumores. Este modelo representa um sistema para se avaliar diversas opções de tratamentos contra o câncer e para estudar a tolerância induzida e imunidade tumoral.

Stabilization of serum antibody responses triggered by initial mucosal contact with the antigen independently of oral tolerance induction

Initial contacts with a T-dependent antigen by mucosal routes may result in oral tolerance, defined as the inhibition of specific antibody formation after subsequent parenteral immunizations with the same antigen. We describe here an additional and permanent consequence of these initial contacts, namely, the blockade of secondary-type responsiveness to subsequent parenteral contacts with the antigen. When repeatedly boosted ip with small doses (3 æg) of ovalbumin (OVA) (or lysozyme), primed B6D2F1 mice showed progressively higher antibody responses. In contrast, mice primed after a single oral exposure to the antigen, although repeatedly boosted, maintained their secondary antibody titers on a level which was inversely proportional to the dose of antigen in the oral pretreatment. This phenomenon also occurred in situations in which oral tolerance was not induced. For example, senile 70-week-old B6D2F1 mice pretreated with a single gavage of 20 mg OVA did not become tolerant, i.e., they formed the same secondary levels of anti-OVA antibodies as non-pretreated mice. However, after 4 weekly challenges with 3 æg OVA ip, orally pretreated mice maintained the same anti-OVA serum levels, whereas the levels of control mice increased sequentially. This "stabilizing" effect of mucosal exposure was dose dependent, occurred with different proteins and was triggered by single or multiple oral or nasal exposures to the antigen

Contribuição ao conhecimento da resposta inflamatória do hospedeiro de leishmaniose mucosa, antes e após o tratamento / Contribution to investigation of the host inflammatory response in mucosal leishmaniasis before and after treatment

A Leishmaniose Tegumentar Americana (LTA), doença endêmica no Brasil, é considerada um grande problema de saúde pública. s em biópsias de pacientes com LM. Foram incluídos vinte pacientes, informados e voluntários, com LM, sendo realizadas biópsias da mucosa afetada antes e após a terapêutica específica para leismaniose, além da obtenção de dados clínicos relevantes. Os preparados foram analisados antes e após a terapêutica, avaliando-se a histopatologia do epitélio e da lâmina própria, com comparação semiquantitativa de eventos, quando necessário. Para a comparação de células e citocinas, áreas delimitadas do epitélio e da lâmina nprópria foram quantificadas para o número de células por campo padrão marcadas nas reações imuno-histoquímicas. Pode-se concluir que o tratamento específico é o causador da redução de lesões inflamatórias menos específicas e desaparecimento das formas amastigotas de Leishmania / American Tegumental Leishmaniasis (ATL), An endemic disease in Brazil, is considered to be a major health problem. When the disease is limited to mucosal involvement (mucosal leismaniasis (ML) mainly caused by Leishmania (V.) braziliensis), important morbidity occurs. We may conclude that specific treatment causes a reduction of the less specific inflammatory lesions and the disappearance of the amastigote forms of Leishmania, although the factors related to the pathogenesis of the lesion. A mised Th1 and Th2 response pattern occurs in ML at the tissue level in the lesions before treatment, persisting after treatment although at a lower level, with reduced overall expression of cytokines, but whit persisting expression of IL-4 and IL-10 expression...

Presence of circulating autoantibodies against bronchial epithelia cell in patients with nonatopic asthma

Allergic response to common environmental agents has been regarded as a main pathogenetic mechanism of bronchial asthma. However, allergic sensitization (atopy) can not be detected in a siginificant number of adult asthmatic patients. The etiology of nonatopic asthma has not yet been defined. To evaluate the possible involvement of autoimmune response against bronchial mucosa in the pathogenesis of nonatopic asthma, we performed indirect immunofluorescence staining of fresh frozen human bronchial mucosa tissue using serum samples from patients with atopic and nonatopic asthma, healthy controls, and patients with systemic lupus erythematosus. On immunostaining, circulating IgG autoantibodies against bronchial mucosa were detected in 2 (9.1%) of 22 patients with nonatopic asthma and in none of 22 patients with atopic asthma and of 22 healthy controls. IgG autoantibodies from the two patients with nonatopic asthma predominantly stained the cytoplasmic membrane of basal cells in bronchial epithelium. Serum samples from 10 patients with systemic lupus erythematosus immunostained the nucleus of epithelial cells in whole layer of bronchial epithelium. This study showed the presence of circulating IgG autoantibodies against the bronchial epithelial cell in a small portion of patients with nonatopic asthma. Further studies may be necessary to evaluate the possible involvement of autoimmune mechanism in the pathogenesis of nonatopic asthma.