Após o nascimento, os recém-nascidos são expostos a vários tipos de micro-organismos, que podem determinar um processo infeccioso devido a sua imaturidade imunológica. Dentro deste processo, a amamentação tem um papel importante pela transferência passiva de imunoglobulina A (IgA). A cavidade oral é a principal porta de entrada destes agentes, especialmente os estreptococos, sendo que alguns colonizam inicialmente como Streptococcus gordonii (SGO), S. sanguinis (SSA) e S. mitis (SMI) e outros podem causar doenças, como S. mutans (SM), por ser o principal agente etiológico da cárie dentária. Pouco se sabe sobre a especificidade de IgA do colostro contra antígenos importantes destes estreptococos, o que pode ajudar na investigação dos mecanismos de estimulação antigênica e desenvolvimento da resposta imune de mucosa. Para tanto, foi avaliado no presente estudo, a especificidade e os níveis de IgA três antígenos de virulência de SM: glucan binding protein B (gbpB), glicosiltransferase (GTF) e antígeno I/II (Ag I/II) envolvidos na capacidade destas bactérias de aderir e acumular no biofilme. Além disso, as glicosiltransferases: 153 kDa de SGO e 170 kDa de SSA e IgA1- protease de SMI (220 kDa) em amostras de colostro humano. Um total de 77 amostras de colostro foram analisadas quanto aos níveis de immunoglobulian A, M e G por ELISA. A complexidade da IgA contra as bactérias foram analisadas por Western blot. Os resultados mostraram que a concentração média de IgA foi de 2850,2 (±2567,2) mg/100 mL sendo estatisticamente maior (p<0.05) dos níveis de IgM e de IgG (respectivamente 321,8±90,3 e 88,3± 51,5 mg/100 mL). A maioria das amostras tiveram níveis detectáveis de anticorpos IgA para extratos de antígenos de bactérias e seus antígenos de virulência, apresentando um elevado número de bandas reativas. Não houve diferença estatisticamente significante no número médio de IgA reativas a Ags entre os antígenos (p>0.4). A detecção de gbpB foi significativamente menor do que os outros antígenos de SM (p<0.05). Assim, o leite materno das primeiras horas após o nascimento apresentou níveis significativos de IgA contra importantes antígenos de virulência dos estreptococos orais estudados, que pode sugerir que a amamentação antes da erupção dos dentes pode interferir no processo de instalação e acumulação destes microorganismos na cavidade oral. / After birth, newborn babies are exposed to several types of microorganisms that can determine an infectious process due to their immunological immaturity. In this case, the feeding plays an important role by passive transfering of immunoglobulin A (IgA). The oral cavity is the main gateway of these agents, especially streptococci, some initially colonize as Streptococcus gordonii (SGO), S. sanguinis (SSA) and S. mitis (SMI) and others can cause diseases such as S. mutans (SM), as the main agent of tooth decay. Little is known about the specific IgA against major antigens of these streptococci which can help in the investigation of antigenic stimulation mechanisms and development of mucosal immune response. Therefore, we evaluated in this study, the specificity and levels of IgA from colostrum against three SM virulence antigens: glucan binding protein B (gbpB), glycosyltransferase (GTF) and antigen I/II (Ag I/II) involved in capacity these bacteria to adhere to and accumulate in the biofilm. Also, the glycosyltransferases: 153 kDa-SGO and 170 kDa-SSA and IgA1- protease of SMI (220 kDa). This study involved 77 samples of colostrum that were analyzed for levels of immunoglobulian A, M and G by Elisa. The specificity of IgA against extracts of SM and initials colonizators (SSA, SMI, SGO) were analyzed by the western blot. The mean concentration of IgA was 2850.2 (± 2567.2) mg/100ml followed by IgM and IgG (respectively 321.8 ± 90.3 and 88.3 ± 51.5), statistically different (p<0.05). Results showed that the majority of samples had detectable levels of IgA antibodies to extracts of bacteria antigens and theirs virulence antigens. To SM, the GbpB was significantly lower detected than others antigens of SM (p<0.05). High complexities of response to Ags were identified in the samples. There were no significant differences in the mean number of IgA-reactive Ags between the antigens (p>0.4). So, the breast milk from first hours after birth presented significant levels of IgA specific against important virulence of antigens those oral streptococci, which can disrupt the installation and accumulation process of these microorganisms in the oral cavity.

Toxoplasma gondii vs radiação ionizante: Imunidade humoral e celular em baço e intestino de camundongos isogênicos imunizados com taquizoítos irradiados por Cobalto 60 Andrés Jimenez Galisteo Jr. Estudamos o desenvolvimento de uma vacina para toxoplasmose utilizando a radiação ionizante como ferramenta. Aqui avaliamos o desenvolvimento da imunidade sistêmica e intestinal e a resistência à infecção, em diferentes camundongos imunizados, por via oral e parenteral, com taquizoítos irradiados a 255 Gy e desafiados com cistos da cepa ME49. Camundongos C57Bl/6j, BALB/c e C57Bl/6j IFN--/- foram imunizados com 107 taquizoitos de T. gondii irradiados a 255Gy por diferentes vias. As preparações de taquizoítos irradiados, por via oral e parenteral, induziram produção de imunoglobulinas IgG e IgA no soro de camundongos, sendo predominante a subclasse de IgG2b, determinadas por ELISA. A produção de IgM foi mínima. Os animais imunizados pela via parenteral, apresentaram uma maturação mais rápida da avidez de anticorpos IgG que os animais imunizados por via oral. Houve excreção de IgG, IgA e IgM nas fezes dos animais imunizados, mais intensa nos animais imunizados por via oral. No estudo da imunidade celular induzida por antígeno e detectada for real-time PCR, houve uma grande produção de IFN- por células esplênicas, menor por células das placas de Peyer intestinais, onde houve maior produção de IL-2. Houve proteção em todos os nossos esquemas avaliados, maior nos animais BALB/c. Os animais deficientes de IFN-, não foram afetados pelo processo de imunização e apresentaram produção de IgG e IgA sérico e excreção de S-IgA e S-IgM nas fezes, com menor numero de cistos cerebrais em animais imunizados por via parenteral. Todos nossos dados apontam para a possibilidade do desenvolvimento de uma vacina oral para toxoplasmose, utilizando taquizoítos irradiados, com aplicação prática na imunização de felinos domésticos e selvagens. / We are developing a vaccine for toxoplasmosis, using ionizing radiation as a tool. Here we analyzed the production of sytemic and intestinal immunity, with protection studies, in several strains of inbred mice, by oral or parenteral route, using 255 Gy irradiated tachyzoites of T. gondii RH strain, with challenge with cysts of ME- 49 strain. C57Bl/6j, BALB/c and C57Bl/6j IFN--/- mice were immunized with 107 irradiated tachyzoites, be parenteral or oral route. Those preparations, both by parenteral or oral routes, induced the production of specific IgG, mainly of the IgG2b subclass, and IgA immunoglobulins in serum, , as determined by ELISA. IgM production was negligible. Parenteral immunized mice showed higher IgG avidity maturation, as compared to oral immunized mice. Fecal excretion of IgG, IgA and IgM was detected in stools of immunized animals, more intense in oral immunized mice. In cellular immunity studies, induced by antigen, with detection of cytokine production by quantitative real-time PCR, there are a great production of IFN- by spleen cells, with lower levels in Peyer patches cells, where there are a greater IL-2 production. Challenge studies in immunized mice demonstrated protection to infection in all used schedules, greater in BALB/c mice. C57Bl/6j IFN--/- mice, when immunized, showed no signs of disease and produced similar or greater levels of antibodies than wild type mice. They also excreted S-IgA and S-IgM in stools, but with low numbers of brain cysts in parenteral immunized mice, despite similar mortality. Our data points to a fair possibility of use of those irradiated parasites as an oral vaccine, devised to use for veterinary or wild felines vaccination, reducing the production of oocysts by those hosts and interrupting the chain transmission of human toxoplasmosis.

Após o nascimento, os recém-nascidos são expostos a vários tipos de micro-organismos, que podem determinar um processo infeccioso devido a sua imaturidade imunológica. Dentro deste processo, a amamentação tem um papel importante pela transferência passiva de imunoglobulina A (IgA). A cavidade oral é a principal porta de entrada destes agentes, especialmente os estreptococos, sendo que alguns colonizam inicialmente como Streptococcus gordonii (SGO), S. sanguinis (SSA) e S. mitis (SMI) e outros podem causar doenças, como S. mutans (SM), por ser o principal agente etiológico da cárie dentária. Pouco se sabe sobre a especificidade de IgA do colostro contra antígenos importantes destes estreptococos, o que pode ajudar na investigação dos mecanismos de estimulação antigênica e desenvolvimento da resposta imune de mucosa. Para tanto, foi avaliado no presente estudo, a especificidade e os níveis de IgA três antígenos de virulência de SM: glucan binding protein B (gbpB), glicosiltransferase (GTF) e antígeno I/II (Ag I/II) envolvidos na capacidade destas bactérias de aderir e acumular no biofilme. Além disso, as glicosiltransferases: 153 kDa de SGO e 170 kDa de SSA e IgA1- protease de SMI (220 kDa) em amostras de colostro humano. Um total de 77 amostras de colostro foram analisadas quanto aos níveis de immunoglobulian A, M e G por ELISA. A complexidade da IgA contra as bactérias foram analisadas por Western blot. Os resultados mostraram que a concentração média de IgA foi de 2850,2 (±2567,2) mg/100 mL sendo estatisticamente maior (p<0.05) dos níveis de IgM e de IgG (respectivamente 321,8±90,3 e 88,3± 51,5 mg/100 mL). A maioria das amostras tiveram níveis detectáveis de anticorpos IgA para extratos de antígenos de bactérias e seus antígenos de virulência, apresentando um elevado número de bandas reativas. Não houve diferença estatisticamente significante no número médio de IgA reativas a Ags entre os antígenos (p>0.4). A detecção de gbpB foi significativamente menor do que os outros antígenos de SM (p<0.05). Assim, o leite materno das primeiras horas após o nascimento apresentou níveis significativos de IgA contra importantes antígenos de virulência dos estreptococos orais estudados, que pode sugerir que a amamentação antes da erupção dos dentes pode interferir no processo de instalação e acumulação destes microorganismos na cavidade oral. / After birth, newborn babies are exposed to several types of microorganisms that can determine an infectious process due to their immunological immaturity. In this case, the feeding plays an important role by passive transfering of immunoglobulin A (IgA). The oral cavity is the main gateway of these agents, especially streptococci, some initially colonize as Streptococcus gordonii (SGO), S. sanguinis (SSA) and S. mitis (SMI) and others can cause diseases such as S. mutans (SM), as the main agent of tooth decay. Little is known about the specific IgA against major antigens of these streptococci which can help in the investigation of antigenic stimulation mechanisms and development of mucosal immune response. Therefore, we evaluated in this study, the specificity and levels of IgA from colostrum against three SM virulence antigens: glucan binding protein B (gbpB), glycosyltransferase (GTF) and antigen I/II (Ag I/II) involved in capacity these bacteria to adhere to and accumulate in the biofilm. Also, the glycosyltransferases: 153 kDa-SGO and 170 kDa-SSA and IgA1- protease of SMI (220 kDa). This study involved 77 samples of colostrum that were analyzed for levels of immunoglobulian A, M and G by Elisa. The specificity of IgA against extracts of SM and initials colonizators (SSA, SMI, SGO) were analyzed by the western blot. The mean concentration of IgA was 2850.2 (± 2567.2) mg/100ml followed by IgM and IgG (respectively 321.8 ± 90.3 and 88.3 ± 51.5), statistically different (p<0.05). Results showed that the majority of samples had detectable levels of IgA antibodies to extracts of bacteria antigens and theirs virulence antigens. To SM, the GbpB was significantly lower detected than others antigens of SM (p<0.05). High complexities of response to Ags were identified in the samples. There were no significant differences in the mean number of IgA-reactive Ags between the antigens (p>0.4). So, the breast milk from first hours after birth presented significant levels of IgA specific against important virulence of antigens those oral streptococci, which can disrupt the installation and accumulation process of these microorganisms in the oral cavity.

The development of mucosal dendritic cells (DCs) in cattle is poorly understood and an analysis of myeloid cells in the bovine small intestine is required to increase our knowledge in this area. The phenotype, frequency and distribution of mucosal myeloid and lymphoid lamina propria leukocytes (LPL) and intraepithelial leukocytes (IEL) in the ileum and jejunum of newborn calves (3-5 weeks old) were analyzed using flow cytometry and immunohistochemistry (IHC). LPL and IEL were isolated through the use of chemical and enzymatic incubations. Costaining with a CD45-specific monoclonal antibody allowed us to exclude all non-leukocytic cells from our analysis of IEL and LPL. The morphology of CD45+CD11c+MHC Class II+ cells isolated from the lamina propria (LP) of ileum and jejunum showed myeloid characteristics, validating the use of CD11c and MHC Class II co-expression to identify myeloid cells. Regional differences in the frequency and number of leukocytes isolated from the IEL and LP compartments of the ileum and jejunum were analyzed in newborn calves. The CD11cHiCD14+ and CD335+ NK cell populations were significantly more abundant in the ileum than the jejunum. IHC was then used to identify the distribution of myeloid cells within the intestine. This analysis confirmed the presence of a variety of myeloid cell populations within the LP. Furthermore, CD11c+ cells were uniquely distributed within the jejunal, but not the ileal IEL compartment. In contrast, CD11b+ cells were present in the ileal, but absent from the jejunal, IEL compartment. A comparison of myeloid cell populations isolated from jejunum and blood dentified distinct mucosal DC populations, such as CD11c+CD13+ cells, which were present in he jejunum but absent from blood. The phenotype, frequency and distribution of IEL and LPL in the ileum and jejunum of weaned calves (6 months old) were then investigated. Significant regional differences were observed when comparing mucosal T cell populations with CD8+ and γδ T cells more abundant in the ileum and CD4+ T cells more abundant in the jejunum. Proportionally, there were no significant differences between the frequency and number of myeloid populations in the two regions. IHC was, once again, used to confirm these unique distributions of cells within each region. CD11b+ cells were present in the LP of both the ileum and jejunum, although a small number of CD11b+ cells were found in the ileal epithelium. CD4+ T cells were restricted to the LP, while CD8+ and γδ T cells were restricted to the IEL compartment. Significant age-related changes were observed when comparing mucosal leukocyte populations in the ileum and jejunum of newborn and 6 month old calves. In the ileum there was an age-related enrichment of CD8+ and γδ T cells, while in the jejunum there was enrichment in CD4+ and CD8+ T cells. In contrast, total myeloid (CD11c+MHC Class II+) cells number remained unchanged but there was a significant age-related enrichment of DC subpopulations (CD13, CD26, CD205). In conclusion, the ileum and jejunum of the newborn calf was populated by diverse myeloid subpopulations, some of which were distinct from myeloid subpopualtions identified in blood. Furthermore, the total number of CD11cHiMHC Class II+ myeloid cells isolated from a 10 cm segment of intestine did not change with age. If neonatal DCs are functionally equivalent to DCs present in weaned calves then the neonatal mucosal immune system appears to have an equivalent capacity to acquire and present antigens acquired from diet, commensal microflora, or pathogens. The one limitation to this conclusion may be the marked difference in the distribution of intraepithelial DC and macrophage distribution when comparing newborn and weaned calves.

The development of mucosal dendritic cells (DCs) in cattle is poorly understood and an analysis of myeloid cells in the bovine small intestine is required to increase our knowledge in this area. The phenotype, frequency and distribution of mucosal myeloid and lymphoid lamina propria leukocytes (LPL) and intraepithelial leukocytes (IEL) in the ileum and jejunum of newborn calves (3-5 weeks old) were analyzed using flow cytometry and immunohistochemistry (IHC). LPL and IEL were isolated through the use of chemical and enzymatic incubations. Costaining with a CD45-specific monoclonal antibody allowed us to exclude all non-leukocytic cells from our analysis of IEL and LPL. The morphology of CD45+CD11c+MHC Class II+ cells isolated from the lamina propria (LP) of ileum and jejunum showed myeloid characteristics, validating the use of CD11c and MHC Class II co-expression to identify myeloid cells. Regional differences in the frequency and number of leukocytes isolated from the IEL and LP compartments of the ileum and jejunum were analyzed in newborn calves. The CD11cHiCD14+ and CD335+ NK cell populations were significantly more abundant in the ileum than the jejunum. IHC was then used to identify the distribution of myeloid cells within the intestine. This analysis confirmed the presence of a variety of myeloid cell populations within the LP. Furthermore, CD11c+ cells were uniquely distributed within the jejunal, but not the ileal IEL compartment. In contrast, CD11b+ cells were present in the ileal, but absent from the jejunal, IEL compartment. A comparison of myeloid cell populations isolated from jejunum and blood dentified distinct mucosal DC populations, such as CD11c+CD13+ cells, which were present in he jejunum but absent from blood. The phenotype, frequency and distribution of IEL and LPL in the ileum and jejunum of weaned calves (6 months old) were then investigated. Significant regional differences were observed when comparing mucosal T cell populations with CD8+ and γδ T cells more abundant in the ileum and CD4+ T cells more abundant in the jejunum. Proportionally, there were no significant differences between the frequency and number of myeloid populations in the two regions. IHC was, once again, used to confirm these unique distributions of cells within each region. CD11b+ cells were present in the LP of both the ileum and jejunum, although a small number of CD11b+ cells were found in the ileal epithelium. CD4+ T cells were restricted to the LP, while CD8+ and γδ T cells were restricted to the IEL compartment. Significant age-related changes were observed when comparing mucosal leukocyte populations in the ileum and jejunum of newborn and 6 month old calves. In the ileum there was an age-related enrichment of CD8+ and γδ T cells, while in the jejunum there was enrichment in CD4+ and CD8+ T cells. In contrast, total myeloid (CD11c+MHC Class II+) cells number remained unchanged but there was a significant age-related enrichment of DC subpopulations (CD13, CD26, CD205). In conclusion, the ileum and jejunum of the newborn calf was populated by diverse myeloid subpopulations, some of which were distinct from myeloid subpopualtions identified in blood. Furthermore, the total number of CD11cHiMHC Class II+ myeloid cells isolated from a 10 cm segment of intestine did not change with age. If neonatal DCs are functionally equivalent to DCs present in weaned calves then the neonatal mucosal immune system appears to have an equivalent capacity to acquire and present antigens acquired from diet, commensal microflora, or pathogens. The one limitation to this conclusion may be the marked difference in the distribution of intraepithelial DC and macrophage distribution when comparing newborn and weaned calves.

The development of mucosal dendritic cells (DCs) in cattle is poorly understood and an analysis of myeloid cells in the bovine small intestine is required to increase our knowledge in this area. The phenotype, frequency and distribution of mucosal myeloid and lymphoid lamina propria leukocytes (LPL) and intraepithelial leukocytes (IEL) in the ileum and jejunum of newborn calves (3-5 weeks old) were analyzed using flow cytometry and immunohistochemistry (IHC). LPL and IEL were isolated through the use of chemical and enzymatic incubations. Costaining with a CD45-specific monoclonal antibody allowed us to exclude all non-leukocytic cells from our analysis of IEL and LPL. The morphology of CD45+CD11c+MHC Class II+ cells isolated from the lamina propria (LP) of ileum and jejunum showed myeloid characteristics, validating the use of CD11c and MHC Class II co-expression to identify myeloid cells. Regional differences in the frequency and number of leukocytes isolated from the IEL and LP compartments of the ileum and jejunum were analyzed in newborn calves. The CD11cHiCD14+ and CD335+ NK cell populations were significantly more abundant in the ileum than the jejunum. IHC was then used to identify the distribution of myeloid cells within the intestine. This analysis confirmed the presence of a variety of myeloid cell populations within the LP. Furthermore, CD11c+ cells were uniquely distributed within the jejunal, but not the ileal IEL compartment. In contrast, CD11b+ cells were present in the ileal, but absent from the jejunal, IEL compartment. A comparison of myeloid cell populations isolated from jejunum and blood dentified distinct mucosal DC populations, such as CD11c+CD13+ cells, which were present in he jejunum but absent from blood. The phenotype, frequency and distribution of IEL and LPL in the ileum and jejunum of weaned calves (6 months old) were then investigated. Significant regional differences were observed when comparing mucosal T cell populations with CD8+ and &#947;&#948; T cells more abundant in the ileum and CD4+ T cells more abundant in the jejunum. Proportionally, there were no significant differences between the frequency and number of myeloid populations in the two regions. IHC was, once again, used to confirm these unique distributions of cells within each region. CD11b+ cells were present in the LP of both the ileum and jejunum, although a small number of CD11b+ cells were found in the ileal epithelium. CD4+ T cells were restricted to the LP, while CD8+ and &#947;&#948; T cells were restricted to the IEL compartment. Significant age-related changes were observed when comparing mucosal leukocyte populations in the ileum and jejunum of newborn and 6 month old calves. In the ileum there was an age-related enrichment of CD8+ and &#947;&#948; T cells, while in the jejunum there was enrichment in CD4+ and CD8+ T cells. In contrast, total myeloid (CD11c+MHC Class II+) cells number remained unchanged but there was a significant age-related enrichment of DC subpopulations (CD13, CD26, CD205). In conclusion, the ileum and jejunum of the newborn calf was populated by diverse myeloid subpopulations, some of which were distinct from myeloid subpopualtions identified in blood. Furthermore, the total number of CD11cHiMHC Class II+ myeloid cells isolated from a 10 cm segment of intestine did not change with age. If neonatal DCs are functionally equivalent to DCs present in weaned calves then the neonatal mucosal immune system appears to have an equivalent capacity to acquire and present antigens acquired from diet, commensal microflora, or pathogens. The one limitation to this conclusion may be the marked difference in the distribution of intraepithelial DC and macrophage distribution when comparing newborn and weaned calves.

Inflammatory Bowel Diseases, Crohn's Disease and Ulcerative colitis, are idiopathic chronic conditions with multifactorial determinants. In general, terms, intestinal inflammation results from abnormal host-microbe interactions. Alterations in homeostasis involve host genetic factors, environmental cues and unique luminal microbial niches. We have examined the coordinated expressions of several molecular targets relevant to the mucosal immune system and identified signature biomarkers of IBD. Qualitative and quantitative changes in the composition of microbiota can be related to unique immuno-phenotypes. This in turn can have more systemic effects that involve energy metabolism. Adiponectin, an adipose tissue derived adipokine, can restore cellular ATP levels and fulfills innate immune functions. We have concluded that IBD might represent a state of adiponectin resistance relating to chronic inflammation and obesity status. Lastly we hypothesized that activation of xenobiotic pathway (AHR-aryl hydrocarbon receptor) can further modulate host immune and metabolic responses, and thus contribute to IBD phenotypes. We found that IBD is associated with robust mucosal, aryl hydrocarbon receptor pathway and related to proinflammatory cytokine secretion. We conclude that IBD heterogeneity is reflected through distinct immunophenotypes. Furthermore, environmental cues that involve the AhR receptor and adipose tissue derived adiponectin are important regulators of the inflammatory process in IBD.

No description available.

Nous avons mis en évidence la présence des phagocytes exprimant le lysozyme dans les Plaque de Peyer chez l’Homme et montré que, comme chez la souris, elles sont principalement localisées dans le SED et sont distinctes des cDC. Dans un deuxième temps, nous avons étudié dans les PP de souris la fonction des différentes populations de phagocytes nouvellement caractérisées. Nous avons en particulier étudié l’impact de la détection d’un acide nucléique d’origine virale par les phagocytes en utilisant un agoniste synthétique du TLR7 : le R848. Bien que TLR7 soit exprimé par les cellules dérivées de monocytes et les DC plasmacytoïdes mais pas par les cDC, nous avons mis en évidence un processus d’activation rapide des cDC impliquant le TNF. Celui-ci conduit à une migration des cDC depuis les villosités adjacentes au dôme vers les IFR et à une forte augmentation de l’expression du CMH-II, des molécules co-stimulatrices ainsi que des gènes dépendants de l’interféron. L’activation du TLR7 induit également une forte expression de la sous unité p40 de l’IL-12 par les LysoDC et certains macrophages. De manière intéressante, nous avons également observé une forte expression d’IL-12 p40 par les LysoDC et certains macrophages peu de temps après le sevrage. Cela nous a conduits à étudier le rôle de cette cytokine dans la mise en place de la réponse immunitaire mucosale. Notre étude a donc des répercussions sur la compréhension des mécanismes conduisant à la mise en place de la réponse immunitaire mucosale en réponse à l’implantation du microbiote intestinal peu de temps après la naissance. / In this study, we first showed that lysozyme expressing cells are found in human PP and share features with their mouse counterpart, such as location and origin. Then, we investigated the behaviour of mouse PP phagocytes upon TLR7 stimulation, using the small synthetic agonist, R848. In PP TLR7 is expressed by monocyte derived cells and plasmacytoid DC, but not by cDC. Nevertheless, TLR7 stimulation triggers a quick activation of cDC. This activation relies on TNF secretion and leads to a massive migration of cDC from the dome associated villi to the IFR and to an increase of MHCII, co-stimulatory molecules and interferon-stimulated gene expression. Stimulation by TLR7 also induces a massive production of IL12p40 by LysoDC and some macrophages. Interestingly, we observed a similar increase of IL-12 p40 production by LysoDC and macrophages shortly after weaning. We thus investigated the impact of Il-12 p40 secretion on the development of the mucosal immune response. Therefore, our study provides clues on the mechanisms involved in the establishment of the mucosal immune response following microbiota colonization.

Chlamydia trachomatis (C. trachomatis) is the most prevalent sexually transmitted bacteria with devastating reproductive consequences that lead to tubal factor infertility (TFI). Recent studies have implicated apoptosis – associated speck – like protein containing a caspase recruitment domain (ASC) as an adaptor of inflammasomes that stimulate IL – 1β and IL – 18 secretion, pro – inflammatory cytokines with critical functions in host defense against a variety of pathogens. Therefore, for the first time, we are reporting the use of ASC-/- mice in a mouse model of Chlamydia infection that might provide some information on the role of inflammasomes in the pathogenesis of Chlamydia infection. In this study, wild type (WT) and ASC-/- mice were infected with Chlamydia. Infectivity, pathology of the upper genital tract (UGT), and, fertility were evaluated. In addition, expression of ASC – dependent inflammasomes and the activation of immune cells within the genital tract (GT) were studied. Results showed that Chlamydia infectivity in ASC-/- mice was significantly higher (p-/- mice which, when compared to infected WT mice, was exhibited by decrease in average number of pups and percent pregnancy. There was also severe UGT damage in ASC-/- mice compared to WT mice, correlating with the higher number of hydrosalpinx observed on the UGT of Chlamydia infected ASC-/- mice. Furthermore, IL – 1β and IL – 18 production as well as immune cell activation were down regulated in the GT of Chlamydia infected ASC-/- mice. This finding indicates that in absence of ASC, host innate and adaptive immunity is impaired. Results imply that ASC plays a protective role in the mucosal immunity against GT Chlamydia infection.