White spots amidst the gold: ultrastructural and histological aspects of the chronic inflammatory response of goldfish with ichthyophthiriasis.

Ichthyophthirius multifiliis, the causative agent of white spot disease, is a ciliated protozoan parasite that infects freshwater fish and induces high mortality. Outbreaks occur both in natural and production sites. The aim of the present study was to describe the lesions caused by chronic infection by I. multifiliis in goldfish (Carassius auratus) from an ornamental fish farm, highlighting important ultrastructural aspects of this protozoan. Damaged skin and gills, collected from fish with white or ulcerative skin lesions, were routinely processed for histological analysis and transmission electron microscopy. The parasitic forms present in the skin were associated with an inflammatory infiltrate consisting of macrophages, lymphocytes and other polymorphonuclear cells. The lesions associated with the presence of the parasite were organized in the form of granulomas, with macrophages in the layers closest to the parasites. A trophont-thickened membrane and induction of granulomatous inflammation were identified in this study as mechanisms for evasion of the immune response. We concluded that the presence of I. multifiliis trophonts resulted in the formation of granulomatous inflammation, whether associated or not with pathogen lysis, suggesting that the parasite can use an inflammatory response to evade the immune response.

White spots amidst the gold: ultrastructural and histological aspects of the chronic inflammatory response of goldfish with ichthyophthiriasis

Ichthyophthirius multifiliis, the causative agent of white spot disease, is a ciliated protozoan parasite that infects freshwater fish and induces high mortality. Outbreaks occur both in natural and production sites. The aim of the present study was to describe the lesions caused by chronic infection by I. multifiliis in goldfish (Carassius auratus) from an ornamental fish farm, highlighting important ultrastructural aspects of this protozoan. Damaged skin and gills, collected from fish with white or ulcerative skin lesions, were routinely processed for histological analysis and transmission electron microscopy. The parasitic forms present in the skin were associated with an inflammatory infiltrate consisting of macrophages, lymphocytes and other polymorphonuclear cells. The lesions associated with the presence of the parasite were organized in the form of granulomas, with macrophages in the layers closest to the parasites. A trophont-thickened membrane and induction of granulomatous inflammation were identified in this study as mechanisms for evasion of the immune response. We concluded that the presence of I. multifiliis trophonts resulted in the formation of granulomatous inflammation, whether associated or not with pathogen lysis, suggesting that the parasite can use an inflammatory response to evade the immune response.

High lysyl oxidase expression is an indicator of poor prognosis in dogs with cutaneous mast cell tumours.

Mast cell tumour (MCT) is one of the most frequent skin tumours in dogs. Due to their unpredictable biological behaviour, MCTs often cause several therapeutic frustrations, leading to investigation regarding prognostic markers. Lysyl oxidase (LOX) is an enzyme that promotes extracellular matrix stability and contributes to cell migration, angiogenesis and epithelial-mesenchymal transition. Its expression positively correlates with poor prognoses in several human and canine mammary cancers. The aim of this study was to characterise the immunohistochemical expression of LOX in MCT samples and compare it with histological grading and post-surgical survival. Twenty-six tumours were submitted to immunohistochemistry for LOX expression evaluation. All samples were positive for LOX, with variable percentages of cytoplasmic and nuclear positivity. Cytoplasmic positivity was significantly higher in high-grade MCTs (P = .0297). Our results indicate that high expression of cytoplasmic LOX in neoplastic mast cells is an indicator of poor prognosis for canine cutaneous MCTs.

Successful use of albendazole and fenbendazole therapy in a cat with persistent diarrhea due Enterocytozoon bieneusi.

Enterocytozoon bieneusi, also known as microsporidia, is an obligate, opportunistic, and neglected intracellular pathogen that causes diarrhea in humans. Although identified in the cat feces by epidemiological studies, no association with diarrhea has been demonstrated. We demonstrated a case of chronic enteritis by E. bieneusi in a 1-year-old male Maine Coon cat, neutered with diarrhea for nine months, by histopathological analysis of gastrointestinal biopsies and PCR of feces. The treatment with albendazole (10 days) followed by fenbendazole (5 days) proved to be effective and safe after diagnosis. This description highlights the need to investigate these pathogens in cases of diarrhea due to their importance in public health since they are zoonotic agents.

Mice with genetic and induced B-cell deficiency as a model for disseminated encephalitozoonosis.

Encephalitozoon cuniculi, an intracellular pathogen, lives in a balanced relationship with immunocompetent individuals based on the activity of T lymphocytes. We previously highlighted the greater susceptibility of B-1 cell-deficient mice (XID mice) to encephalitozoonosis. This study aimed to develop a model of disseminated and severe encephalitozoonosis in mice with combined immunodeficiency to elucidate the role of B cells. To address this objective, cyclophosphamide (Cy)-treated BALB/c and XID mice were inoculated with E. cuniculi, followed by the evaluation of the immune response and histopathological lesions. Immunosuppressed BALB/c mice manifested no clinical signs with an increase in the populations of T lymphocytes and macrophages in the spleen. Immunosuppressed and infected XID mice revealed elevated T cells, macrophages populations, and pro-inflammatory cytokines levels (IFN-γ, TNF-α, and IL-6) with the presence of abdominal effusion and lesions in multiple organs. These clinical characteristics are associated with extensive and severe encephalitozoonosis. The symptoms and lesion size were reduced, whereas B-2 and CD4+ T cells populations were increased in the spleen by transferring B-2 cells adoptive to XID mice. Moreover, B-1 cells adoptive transfer upregulated the peritoneal populations of B-2 cells and macrophages but not T lymphocytes and decreased the symptoms. Herein, we speculated the consistency in the development of severe and disseminated encephalitozoonosis in mice with genetic deficiency of Bruton's tyrosine kinase (Btk) associated with Cy immunosuppression develop with that of the models with T cell deficiency. Taken together, these data emphasized the crucial role of B cells in the protective immune response against encephalitozoonosis.

Opportunistic pneumonia caused by E. cuniculi in mice immunosuppressed with cyclophosphamide

Opportunistic fungal pneumonia is a cause of concern in immunocompromised patients due to its high morbidity and mortality rates. One such opportunistic agent affecting immunocompromised patients is the microsporidia called Encephalitozoon cuniculi. This study aimed to evaluate pneumonia caused by E. cuniculi in mice treated with the immunosuppressive agent cyclophosphamide (Cy). This study also aimed to describe the immune cells associated with the microsporidial pneumonia. C57BL/6 mice were infected intravenously with E. cuniculi spores and treated with Cy (75 mg/kg/week, intraperitoneally). Thirty days post-infection, the fungal burden (qPCR), histopathological lesions, cytokine production, and the phenotype of the immune cells in the lung parenchyma were evaluated. Histologically, interstitial pneumonia with lymphocytic infiltrate was observed in the infected animals. The infiltrate mainly consisted of CD8+ and CD4+ T lymphocytes, with reduced populations of B lymphocytes and macrophages. The production of tumor necrosis factor-alpha (TNF-α) was significant in the animals of the infected groups. Also, the fungal burden was higher in the Cy-treated animals, which was confirmed by the immunohistochemical observation of spores. These results demonstrated that E. cuniculi infection of C57BL/6 mice caused lymphocytic interstitial pneumonia (characterized by a predominant lymphocytic infiltrate), which was aggravated by Cy-induced immunosuppression. Thus, these results can be used to understand the different pathological, immunological, and therapeutic aspects of lymphocytic interstitial pneumonia.

Mice with genetic and induced B-cell deficiency as a model for disseminated encephalitozoonosis

Encephalitozoon cuniculi, an intracellular pathogen, lives in a balanced relationship with immunocompetent individuals based on the activity of T lymphocytes. We previously highlighted the greater susceptibility of B-1 cell-deficient mice (XID mice) to encephalitozoonosis. This study aimed to develop a model of disseminated and severe encephalitozoonosis in mice with combined immunodeficiency to elucidate the role of B cells. To address this objective, cyclophosphamide (Cy)-treated BALB/c and XID mice were inoculated with E. cuniculi, followed by the evaluation of the immune response and histopathological lesions. Immunosuppressed BALB/c mice manifested no clinical signs with an increase in the populations of T lymphocytes and macrophages in the spleen. Immunosuppressed and infected XID mice revealed elevated T cells, macrophages populations, and pro-inflammatory cytokines levels (IFN-γ, TNF-α, and IL-6) with the presence of abdominal effusion and lesions in multiple organs. These clinical characteristics are associated with extensive and severe encephalitozoonosis. The symptoms and lesion size were reduced, whereas B-2 and CD4+ T cells populations were increased in the spleen by transferring B-2 cells adoptive to XID mice. Moreover, B-1 cells adoptive transfer upregulated the peritoneal populations of B-2 cells and macrophages but not T lymphocytes and decreased the symptoms. Herein, we speculated the consistency in the development of severe and disseminated encephalitozoonosis in mice with genetic deficiency of Bruton’s tyrosine kinase (Btk) associated with Cy immunosuppression develop with that of the models with T cell deficiency. Taken together, these data emphasized the crucial role of B cells in the protective immune response against encephalitozoonosis.

Galectin-3 immunolabelling correlates with BCL2 expression in canine cutaneous mast cell tumours.

Mast cell tumour (MCT) is the most frequent skin neoplasm in dogs. These tumours are characterised by variable behaviour and clinical presentation that make prognosis an important and challenging task in the veterinary practice. Galectin-3 (Gal-3) is known to influence several biological processes that are important in the cancer context and has been described as a prognostic marker for several human cancers. The aim of the present work was to characterise Gal-3 immunolabelling in canine cutaneous MCTs and to investigate its value as a prognostic marker for the disease. Thirty-four random cases of canine cutaneous MCT that were surgically treated with wide margins were included in this study. Gal-3 expression was evaluated using immunohistochemistry and the results were compared with the expression of apoptosis-related proteins, Ki67 index, histopathological grades, mortality due to the disease and post-surgical survival. The majority of the MCTs (65.8%) were positive for Gal-3. Gal-3 immunolabelling was variable among the samples (2.7%-86.8% of the neoplastic cells). The protein was located in the cytoplasm or in the cytoplasm and the nucleus. Gal-3 positivity was correlated with BCL2 expression (P < 0.001; r = 0.604), but not with Ki67 and BAX. No significant differences were detected between histological grades or in the survival analysis. Gal-3 expression correlates with BCL2 expression in MCTs. Although an efficient marker for several human neoplasms, the results presented herein suggest that Gal-3 immunolabelling is not an independent prognostic indicator for this disease.

Intratumoral T-Lymphocyte Subsets in Canine Oral Melanoma and Their Association With Clinical and Histopathological Parameters.

Canine oral melanoma is a common, aggressive tumor with limited treatment options. Tumor-infiltrating lymphocytes (TILs) are important in antitumor immunity. This study used histopathology and immunophenotyping by flow cytometry to evaluate the presence and distribution of TILs in canine oral melanoma, including the frequency of CD8+ T cells, CD4+ T cells, and regulatory T cells. Fifty samples of oral melanoma from 45 dogs that did not receive treatment prior to surgery were included in the study. The distribution of TILs in the tissue (brisk, nonbrisk, and absent) was evaluated in 48 samples. Twenty-eight (58%) samples had a brisk distribution pattern, 10 (21%) samples had a nonbrisk pattern, and 10 (21%) samples had an absent TIL pattern. Comparing the histological evaluation and the immunophenotyping data, it was observed that samples with a brisk TIL pattern had a higher frequency of CD8+ T lymphocytes (P = .05) and a lower frequency of CD4+/CD25+/FoxP3+ Tregs (P = .03), compared to the samples with nonbrisk and absent infiltrate patterns. Patients with a higher survival rate had higher TIL scores (P = .002), a brisk or nonbrisk TIL pattern (P = .001), and an increased frequency of CD8+ T lymphocytes infiltrating the tumor (P = .003). Our analysis suggests that the evaluation of TILs in canine oral melanoma is relevant to predict tumor aggressiveness and patient prognosis.

Inhibitory Effects of a Reengineered Anthrax Toxin on Canine Oral Mucosal Melanomas.

Canine oral mucosal melanomas (OMM) are the most common oral malignancy in dogs and few treatments are available. Thus, new treatment modalities are needed for this disease. Bacillus anthracis (anthrax) toxin has been reengineered to target tumor cells that express urokinase plasminogen activator (uPA) and metalloproteinases (MMP-2), and has shown antineoplastic effects both, in vitro and in vivo. This study aimed to evaluate the effects of a reengineered anthrax toxin on canine OMM. Five dogs bearing OMM without lung metastasis were included in the clinical study. Tumor tissue was analyzed by immunohistochemistry for expression of uPA, uPA receptor, MMP-2, MT1-MMP and TIMP-2. Animals received either three or six intratumoral injections of the reengineered anthrax toxin prior to surgical tumor excision. OMM samples from the five dogs were positive for all antibodies. After intratumoral treatment, all dogs showed stable disease according to the canine Response Evaluation Criteria in Solid Tumors (cRECIST), and tumors had decreased bleeding. Histopathology has shown necrosis of tumor cells and blood vessel walls after treatment. No significant systemic side effects were noted. In conclusion, the reengineered anthrax toxin exerted inhibitory effects when administered intratumorally, and systemic administration of this toxin is a promising therapy for canine OMM.

Cyclophosphamide Treatment Mimics Sub-Lethal Infections With Encephalitozoon intestinalis in Immunocompromised Individuals.

Microsporidia, including Encephalitozoon intestinalis, are emerging pathogens which cause opportunistic infections in immunocompromised patients, such as those with AIDS, cancer, the elderly and people on immunosuppressive drugs. Intestinal mucosa (IM) is crucial for developing an efficient adaptive immune response against pathogenic micro-organisms, thereby preventing their colonization and subsequent infection. As immunosuppressive drugs affect the intestinal immune response is little known. In the present study, we investigated the immune response to E. intestinalis infection in the IM and gut-associated lymphoid tissue (GALT) in cyclophosphamide (Cy) immunosuppressed mice, to mimic an immunocompromised condition. Histopathology revealed lymphoplasmacytic enteritis at 7 and 14 days-post-infection (dpi) in all infected groups, however, inflammation diminished at 21 and 28 dpi. Cy treatment also led to a higher number of E. intestinalis spores and lesions, which reduced at 28 dpi. In addition, flow cytometry analysis demonstrated CD4+ and CD8+ T cells to be predominant immune cells, with up-regulation in both Th1 and Th2 cytokines at 7 and 14 dpi, as demonstrated by histopathology. In conclusion, Cy treatment reduced GALT (Peyer's plaques and mesenteric lymph nodes) and peritoneum populations but increased the T-cell population in the intestinal mucosa and the production of pro-and anti-inflammatory cytokines, which were able to eliminate this opportunistic fungus and reduced the E. intestinalis infection.

Intratumoral collagen index predicts mortality and survival in canine cutaneous mast cell tumours.

BACKGROUND: Mast cell tumours (MCTs) constitute almost 25% of cutaneous neoplasms in dogs. Their biological behaviour is predicted using histopathological grading which is based on several subjective criteria that are vulnerable to intra- and interobserver variability. To improve the prediction of the biological behaviour, several complementary markers have been studied. The integrity of the extracellular matrix (ECM) may play a protective role against tumoral progression, and favour cellular proliferation, angiogenesis, invasion and metastases when altered. HYPOTHESIS/OBJECTIVES: To evaluate the quantification of collagen and elastic fibres as prognostic markers for MCTs. ANIMALS: Thirty-eight random cases of canine cutaneous MCT surgically treated with wide margins were included. METHODS AND MATERIALS: Intratumoral collagen and elastic fibres were identified and quantified on histological sections stained with Masson's trichrome, Picrosirius red and Verhoeff; the results were compared with histopathological grades, mortality due to the disease and postsurgical survival. RESULTS: Morphometric analysis revealed a significant relationship between histopathological grade and intratumoral collagen index (CoI). In addition, the CoI was considered an independent indicator for mortality and postsurgical survival. CONCLUSIONS AND CLINICAL IMPORTANCE: These results support the importance of the CoI in the grading and prognosis of MCTs, suggesting that preservation and/or synthesis of collagen have the potential to become targets for MCT therapeutics.

Cyclophosphamide treatment mimics sub-lethal infections with encephalitozoon intestinalis in immunocompromised individuals

Microsporidia, including Encephalitozoon intestinalis, are emerging pathogens which cause opportunistic infections in immunocompromised patients, such as those with AIDS, cancer, the elderly and people on immunosuppressive drugs. Intestinal mucosa (IM) is crucial for developing an efficient adaptive immune response against pathogenic micro-organisms, thereby preventing their colonization and subsequent infection. As immunosuppressive drugs affect the intestinal immune response is little known. In the present study, we investigated the immune response to E. intestinalis infection in the IM and gut-associated lymphoid tissue (GALT) in cyclophosphamide (Cy) immunosuppressed mice, to mimic an immunocompromised condition. Histopathology revealed lymphoplasmacytic enteritis at 7 and 14 days-post-infection (dpi) in all infected groups, however, inflammation diminished at 21 and 28 dpi. Cy treatment also led to a higher number of E. intestinalis spores and lesions, which reduced at 28 dpi. In addition, flow cytometry analysis demonstrated CD4+ and CD8+ T cells to be predominant immune cells, with up-regulation in both Th1 and Th2 cytokines at 7 and 14 dpi, as demonstrated by histopathology. In conclusion, Cy treatment reduced GALT (Peyer’s plaques and mesenteric lymph nodes) and peritoneum populations but increased the T-cell population in the intestinal mucosa and the production of pro-and anti-inflammatory cytokines, which were able to eliminate this opportunistic fungus and reduced the E. intestinalis infection.

Cyclophosphamide treatment mimics sub-lethal infections with encephalitozoon intestinalis in immunocompromised individuals

Microsporidia, including Encephalitozoon intestinalis, are emerging pathogens which cause opportunistic infections in immunocompromised patients, such as those with AIDS, cancer, the elderly and people on immunosuppressive drugs. Intestinal mucosa (IM) is crucial for developing an efficient adaptive immune response against pathogenic micro-organisms, thereby preventing their colonization and subsequent infection. As immunosuppressive drugs affect the intestinal immune response is little known. In the present study, we investigated the immune response to E. intestinalis infection in the IM and gut-associated lymphoid tissue (GALT) in cyclophosphamide (Cy) immunosuppressed mice, to mimic an immunocompromised condition. Histopathology revealed lymphoplasmacytic enteritis at 7 and 14 days-post-infection (dpi) in all infected groups, however, inflammation diminished at 21 and 28 dpi. Cy treatment also led to a higher number of E. intestinalis spores and lesions, which reduced at 28 dpi. In addition, flow cytometry analysis demonstrated CD4+ and CD8+ T cells to be predominant immune cells, with up-regulation in both Th1 and Th2 cytokines at 7 and 14 dpi, as demonstrated by histopathology. In conclusion, Cy treatment reduced GALT (Peyer’s plaques and mesenteric lymph nodes) and peritoneum populations but increased the T-cell population in the intestinal mucosa and the production of pro-and anti-inflammatory cytokines, which were able to eliminate this opportunistic fungus and reduced the E. intestinalis infection.

Nanog Expression and Proliferation Indices in Canine Cutaneous Mast Cell Tumors.

Mast cell tumors are one of the most frequent skin tumors in dogs. Treatment decisions often depend on a wide range of clinical information and the main criteria for prognostic formulation are histological grade, mitotic count, Ki67 index, and KIT immunostaining pattern. NANOG is a pluripotency factor expressed by normal and cancer stem cells, which is a prognostic marker and a potential therapeutic target for several human tumors. In the present study, mast cell tumor samples from 41 dogs were evaluated for NANOG and Ki67 by immunohistochemistry. All samples were positive for NANOG but its expression was not correlated with Ki67 index and no significant differences were found with respect to histopathological grades, disease-related mortality, or survival. Our results suggest that, although related to pluripotency, NANOG expression does not correlate with proliferative activity, and is not a reliable prognostic factor for canine cutaneous mast cell tumors.

Infecção das brânquias de tilápia do Nilo (Oreochromis niloticus) por Myxosporea / Infection of the gills of Nile tilapia (Oreochromis niloticus) by Myxosporea

Neste estudo, 85 tilápias do Nilo (Oreochromis niloticus Linnaeus, 1758) foram coletadas em um lago de pesca recreativa (n = 35) e no lago do parque do Ibirapuera (n = 50), ambos localizados na cidade de São Paulo. Após a eutanásia, as brânquias dos peixes foram examinadas a fresco e por técnicas histológicas para identificar mixosporídeos. Foram observados mixosporídeos somente nos peixes capturados no lago de pesca recreativa com prevalência de 45,7% (16/35). Os esporos de Henneguya sp. foram encontrados em esfregaços a fresco (11,4%, 4/35). A prevalência de Myxobolus sp. foi de 34,3% (12/35), sendo os plasmódios deste gênero identificados de acordo com a localização nas brânquias, no epitélio (75%, 9/12), nos vasos sanguíneos (16,2%, 2/12), e na musculatura branquial (0,8%, 1/12). A presença de mixosporídeos estava relacionada com hiperplasia epitelial, fusão das lamelas, hiperplasia de células mucosas, reação inflamatória e outras alterações patológicas. Assim conclui-se que as prevalências de Myxobolus sp. e Henneguya sp. nas brânquias de O. niloticus foram altas e estavam associadas à lesões histopatológicas significantes, o que evidencia a importância desses cnidários patogênicos para as culturas peixes.(AU)

In this study, 85 Nile tilapia (Oreochromis niloticus Linnaeus, 1758) were collected in recreational fishing lake (n=35) and Lake Ibirapuera Park (n=50), both located in the city of São Paulo. After euthanasia, the fish gills were examined fresh and after histological techniques for the presence of myxosporea. Myxosporeans were observed only in recreational fishing lake with a prevalence of 45.7% (16/35). Henneguya sp. (11.4%, 4/35) and Myxobolus sp. (34.3%, 12/35) were myxosporeans observed in this study. Spores of Henneguya sp. were found in smears fresh gills. The plasmodium of Myxobolus found was of the types epithelial (75%, 9/12), vascular (16.2%, 2/12), and muscle, muscle located in the gills (0.8%; 1/12). The presence of myxosporea was related to epithelial hyperplasia, fusion of lamellae, hyperplasia of mucous cells, inflammation and other pathological changes. Thus it is concluded that prevalence of Myxobolus sp. and Henneguya sp. in gills of O. niloticus was high and was associated with significant histopathological lesions, which highlights the importance of these protozoa to fish cultures.(AU)

Effects of short-term dietary restriction and glutamine supplementation in vitro on the modulation of inflammatory properties.

OBJECTIVE: Dietary restriction (DR) is a nutritional intervention that exerts profound effects on biochemical and immunologic parameters, modulating some inflammatory properties. Glutamine (GLN) is a conditionally essential amino acid that can modulate inflammatory properties. However, there is a lack of data evaluating the effects of DR and GLN supplementation, especially in relation to inflammatory cytokine production and the expression of transcription factors such as nuclear factor (NF)-κB. METHODS: We subjected 3-mo-old male Balb/c mice to DR by reducing their food intake by 30%. DR animals lost weight and showed reduced levels of serum triacylglycerols, glucose, cholesterol, and calcium as well as a reduction in bone density. Additionally, blood, peritoneal, and spleen cellularity were reduced, lowering the number of peritoneal F4/80- and CD86-positive cells and the total number of splenic CD4- and CD8-positive cells. RESULTS: The production of interleukin (IL)-10 and the expression of NF-κB in splenic cells were not affected by DR or by GLN supplementation. However, peritoneal macrophages from DR animals showed reduced IL-12 and tumor necrosis factor-α production and increased IL-10 production with reduced phosphorylation of NF-κB expression. Additionally, GLN was able to modulate cytokine production by peritoneal cells from the control group, although no effects were observed in cells from the DR group. CONCLUSION: DR induces biochemical and immunologic changes, in particular by reducing IL-12 and tumor necrosis factor-α production by macrophages and clearly upregulating IL-10 production, whereas GLN supplementation did not modify these parameters in cells from DR animals.

B-1 cells upregulate CD8 T lymphocytes and increase proinflammatory cytokines serum levels in oral encephalitozoonosis.

Microsporidia are intracellular pathogens that cause severe disease in immunocompromised humans and animals. We recently demonstrated that XID mice are more susceptible to Encephalitozoon cuniculi infection by intraperitoneal route, evidencing the role of B-1 cells in resistance against infection. The present study investigated the resistance and susceptibility against E. cuniculi oral infection, including the role of B-1 cells. BALB/c and BALB/c XID (B-1 cells deficient) mice were orally infected with E. cuniculi spores. No clinical symptoms were observed in infected animals; histopathology showed lymphoplasmocytic enteritis with degeneration of the apexes of the villi in all infected groups. Higher parasite burden was observed in infected BALB/c XID mice. In the spleen and peritoneum, all infected mice showed a decrease of lymphocytes, including CD8+ T cells, mostly in infected BALB/c XID mice. Adoptive transfer of B-1 cells (XID + B-1) was associated with a lower parasite burden. Pro-inflammatory cytokines (IFN-γ, TNF-α and IL-6) increased mostly in infected XID + B1 mice. Together, the present results showed that BALB/c XID mice infected by the oral route were more susceptible to encephalitozoonosis than BALB/c mice, demonstrating the B-1 cells importance in the control of the immune response against oral E. cuniculi infection.

Infecção das brânquias de tilápia do Nilo (Oreochromis niloticus) por Myxosporea

Neste estudo, 85 tilápias do Nilo (Oreochromis niloticus Linnaeus, 1758) foram coletadas em um lago de pesca recreativa (n = 35) e no lago do parque do Ibirapuera (n = 50), ambos localizados na cidade de São Paulo. Após a eutanásia, as brânquias dos peixes foram examinadas a fresco e por técnicas histológicas para identificar mixosporídeos. Foram observados mixosporídeos somente nos peixes capturados no lago de pesca recreativa com prevalência de 45,7% (16/35). Os esporos de Henneguya sp. foram encontrados em esfregaços a fresco (11,4%, 4/35). A prevalência de Myxobolus sp. foi de 34,3% (12/35), sendo os plasmódios deste gênero identificados de acordo com a localização nas brânquias, no epitélio (75%, 9/12), nos vasos sanguíneos (16,2%, 2/12), e na musculatura branquial (0,8%, 1/12). A presença de mixosporídeos estava relacionada com hiperplasia epitelial, fusão das lamelas, hiperplasia de células mucosas, reação inflamatória e outras alterações patológicas. Assim conclui-se que as prevalências de Myxobolus sp. e Henneguya sp. nas brânquias de O. niloticus foram altas e estavam associadas à lesões histopatológicas significantes, o que evidencia a importância desses cnidários patogênicos para as culturas peixes.

B-1 cells upregulate CD8 T lymphocytes and increase proinflammatory cytokines serum levels in oral encephalitozoonosis

Microsporidia are intracellular pathogens that cause severe disease in immunocompromised humans and animals. We recently demonstrated that XID mice are more susceptible to Encephalitozoon cuniculi infection by intraperitoneal route, evidencing the role of B-1 cells in resistance against infection. The present study investigated the resistance and susceptibility against E. cuniculi oral infection, including the role of B-1 cells. BALB/c and BALB/c XID (B-1 cells deficient) mice were orally infected with E. cuniculi spores. No clinical symptoms were observed in infected animals; histopathology showed lymphoplasmocytic enteritis with degeneration of the apexes of the villi in all infected groups. Higher parasite burden was observed in infected BALB/c XID mice. In the spleen and peritoneum, all infected mice showed a decrease of lymphocytes, including CD8(+) T cells, mostly in infected BALB/c XID mice. Adoptive transfer of B-1 cells (XID thorn B-1) was associated with a lower parasite burden. Pro-inflammatory cytokines (IFN-gamma, TNF-alpha and IL-6) increased mostly in infected XID + B1 mice. Together, the present results showed that BALB/c XID mice infected by the oral route were more susceptible to encephalitozoonosis than BALB/c mice, demonstrating the B-1 cells importance in the control of the immune response against oral E. cuniculi infection.