Maldonado Rivera J E, Hecker Y P, Burucúa M M, Cirone K M, Cheuquepán F A, Fiorani F, Dorsch M A, Colque L A, Cantón G J, Marin M S, Moore D P
Faculty of Agrarian Sciences, National University of Mar del Plata, Argentina; Faculty of Agricultural Sciences, University of Cuenca, Ecuador.
Institute of Innovation for Agricultural Production and Sustainable Development (IPADS Balcarce), Argentina.
Mol Immunol. 2021 Apr;132:53-59. doi: 10.1016/j.molimm.2021.01.016. Epub 2021 Feb 2.
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 IgG/IgG ratios <1 and high avidity specific IgG. As expected, colostrum samples of these animals exhibited a high IgG concentration and elevated avidity values. Three out of four calves from N. caninum-infected heifers had specific IgG with IgG/IgG ratios>1 and lower avidity values before colostrum intake. Interestingly, both IgG/IgG 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.
犬新孢子虫是全球范围内导致牛流产的主要原因。研究针对犬新孢子虫的免疫反应对于理解其流行病学、发病机制、诊断，以及最终预防和控制牛新孢子虫病至关重要。在此，我们测定了天然免疫成分内体RNA感应Toll样受体（TLRs）、BMAP28抗菌肽、肿瘤坏死因子-α（TNF-α）和白细胞介素-10（IL-10）的基因表达，并对妊娠210天时受到犬新孢子虫感染的初产母牛、初乳及其犊牛在分娩时的IgG比率和亲和力变化进行了特征分析。与 mock感染对照组相比，在来自犬新孢子虫感染初产母牛的犊牛的初乳、外周血单个核细胞（PBMC）和脐带中均观察到BMAP28表达增加。此外，在脐带中观察到TLR7和IL-10表达水平有统计学意义的下降，这表明机体试图避免针对该寄生虫的过度免疫反应。在分娩时，感染组的血清和初乳样本显示出特异性抗犬新孢子虫IgG。感染的初产母牛显示IgG/IgG比率<1以及高亲和力的特异性IgG。正如预期的那样，这些动物的初乳样本显示出高IgG浓度和升高的亲和力值。来自犬新孢子虫感染初产母牛的四头犊牛中有三头在摄入初乳前具有特异性IgG，其IgG/IgG比率>1且亲和力值较低。有趣的是，初乳摄入后，血清反应阳性的犊牛的IgG/IgG比率和亲和力值均增加。总体而言，本研究提供了关于先天性感染犊牛新生儿免疫的新信息，这对于理解如何操纵免疫途径或利用免疫成分以改善对新孢子虫病的保护至关重要。
