RESUMO
Neospora caninum is a leading cause of abortion in cattle worldwide. The study of the immune response against N. caninum is critical to understand its epidemiology, pathogenesis, diagnosis and, ultimately, in preventing and controlling bovine neosporosis. Herein, we determined the gene expression of innate immune components endosomal RNA-sensing TLRs, BMAP28 cathelicidin, TNF-α and IL-10 and characterized the variation in both IgG ratio and avidity at delivery in N. caninum-infected heifers challenged at day 210 of gestation, colostrum and their calves. Increased BMAP28 expression was observed not only in colostrum but also in peripheral blood mononuclear cells (PBMC) and umbilical cord of calves from N. caninum-infected heifers in comparison with mock-infected control group. In addition, statistically significant decrease of TLR7 and IL-10 expression levels were observed in umbilical cord, suggesting an attempt to avoid an exacerbated immune response against the parasite. At delivery, serum and colostrum samples from infected group evidenced specific IgG anti-N. caninum. Infected heifers showed IgG1/IgG2 ratios <1 and high avidity specific IgG. As expected, colostrum samples of these animals exhibited a high IgG1 concentration and elevated avidity values. Three out of four calves from N. caninum-infected heifers had specific IgG with IgG1/IgG2 ratios>1 and lower avidity values before colostrum intake. Interestingly, both IgG1/IgG2 ratios and avidity values increased in seropositive calves after colostrum intake. Overall, this study provides novel information on neonatal immunity in congenitally infected calves, which is essential to understand how the immune pathways could be manipulated or immune components could be employed in order to improve protection against neosporosis.
Assuntos
Bovinos/imunologia , Colostro/imunologia , Regulação da Expressão Gênica no Desenvolvimento/imunologia , Imunidade Humoral , Imunidade Inata , Neospora/imunologia , Receptores Toll-Like/metabolismo , Animais , Anticorpos Antiprotozoários/imunologia , Bovinos/embriologia , Bovinos/metabolismo , Bovinos/parasitologia , Doenças dos Bovinos/genética , Doenças dos Bovinos/imunologia , Doenças dos Bovinos/metabolismo , Doenças dos Bovinos/parasitologia , Feminino , Imunoglobulina G/imunologia , Interleucina-10/genética , Interleucina-10/metabolismo , Leucócitos Mononucleares/imunologia , Leucócitos Mononucleares/metabolismo , Gravidez , Proteínas/genética , Proteínas/metabolismo , Receptor 7 Toll-Like/genética , Receptor 7 Toll-Like/metabolismo , Receptores Toll-Like/genética , Fator de Necrose Tumoral alfa/genética , Fator de Necrose Tumoral alfa/metabolismo , Cordão Umbilical/metabolismoRESUMO
The aim of this study was to describe bovine neosporosis in dairy cattle from the Sierra region, Ecuador. A case-control study was performed on 841 dairy cattle from 5 dairy herds. The overall seroprevalence was 23.4% having significant association between abortion and seropositivity (p < .05). Additionally, 46 fetuses were recovered from a local slaughterhouse to evaluate the frequency of vertical transmission. Seventeen and 3 fetuses were positive by PCR and had compatible histopathological lesions, respectively. N. caninum infection must be considered as a relevant cause of reproductive losses in Ecuador.
Assuntos
Aborto Animal/epidemiologia , Doenças dos Bovinos/epidemiologia , Coccidiose/veterinária , Neospora/isolamento & purificação , Aborto Animal/parasitologia , Animais , Bovinos , Doenças dos Bovinos/parasitologia , Coccidiose/epidemiologia , Coccidiose/parasitologia , Indústria de Laticínios , Equador/epidemiologia , Feminino , Prevalência , Estudos SoroepidemiológicosRESUMO
The aim of this study was to describe the lectin-binding pattern in the placentas of cows infected experimentally with Neospora caninum. Four cows were inoculated intravenously with 1 × 108 tachyzoites of the NC-1 strain of N. caninum at 150 ± 7 days of pregnancy. Two control cows were administered a placebo. An indirect fluorescence antibody test (IFAT) was performed on serum samples obtained before and after the inoculation. The cows were killed at 30 and 37 days post inoculation. Samples of placenta were taken for histopathology and lectin histochemistry. Fetal tissues and fluids were collected for histopathology and IFAT, respectively. All infected cows had high antibody titres. All fetuses had characteristic histopathological lesions, including non-suppurative meningoencephalitis, myocarditis, hepatitis and myositis, suggesting N. caninum infection. Only two infected fetuses developed specific antibodies. Mild non-suppurative inflammatory infiltrates were recorded in the placentae. Differences in the lectin-binding pattern were observed between infected animals and controls in the glycocalyx (CON-A and WGA) and apical cytoplasm (RCA-I and CON-A) of the trophoblastic cells; giant trophoblastic cells (CON-A and DBA); glycocalyx (PNA, WGA) and apical cytoplasm (CON-A, WGA, PNA, DBA and RCA-I) of endometrial cells; trophoblast of the interplacentomal region (WGA); endothelium (CON-A, SBA, RCA-1 and WGA); and finally, mesenchyme (CON-A, RCA-1, SBA, PNA and DBA). These findings indicate that there is a distinctive pattern of lectin binding in the placenta of cattle infected with N. caninum. The direct effect of the presence of the protozoa as well as the altered expression of cytokines could explain these changes in the maternofetal interface.
