Abstract：
Mycobacterium avium ssp. paratuberculosis (MAP) is the causative agent of paratuberculosis (PTB), a widespread chronic enteritis of ruminants. The progression of the infection depends on the containment action of innate and cell-mediated immunity (CMI), and it is related to environmental and genetic factors. In particular, PTB susceptibility seems to be associated with specific genes coding for immune regulators involved in the cell-mediated response during the infection. The aim of this preliminary study was to verify, in Italian beef cattle, an association between MAP infectious status and the presence of single nucleotide polymorphisms (SNPs) in candidate genes. To the best of our knowledge, this is the first investigation conducted on a native beef cattle breed, known as Marchigiana, reared in Central Italy. The present research, based on a longitudinal study, aimed to identify and correlate phenotypic and genetic profiles characteristic of the subjects potentially able to contrast or contain PTB. In a MAP-infected herd, ELISA, IFN-γ tests, qPCR, and cultures were performed at a follow-up, occurring within a period ranging from three to six years, to evaluate the individual state of infection. Animals testing positive for at least one test were considered infected. DNA samples of 112 bovines, with known MAP statuses, were analyzed to verify an association with SNPs in the genes encoding gamma-interferon (BoIFNG), interleukin receptor 10 (IL10RA), interleukin receptor 12 (IL12RB2), and toll-like receptors (TLR1, TLR2, TLR4). Regarding statistical analysis, the differences among target genes and pairs of alleles in the analyzed groups of animals, were evaluated at a significance level of p < 0.05. For IL10RA and for IL12RB2 genes, relevant differences in genotypic frequencies among the considered cattle groups were observed. For all candidate genes studied in this investigation, SNP genotypes already associated with PTB resistance were found more frequently in our population, suggesting potential resistance traits in the Marchigiana breed.
摘要：
鸟分枝杆菌ssp。副结核病（MAP）是副结核病（PTB）的病原体，反刍动物广泛的慢性肠炎。感染的进展取决于先天和细胞介导的免疫（CMI）的遏制作用，它与环境和遗传因素有关。特别是,PTB易感性似乎与编码参与感染过程中细胞介导反应的免疫调节剂的特定基因有关。这项初步研究的目的是验证，在意大利肉牛中，MAP感染状态与候选基因中存在单核苷酸多态性（SNP）之间的关联。据我们所知,这是对本地肉牛品种进行的首次调查，被称为Marchigiana,在意大利中部饲养。目前的研究,基于纵向研究，旨在鉴定和关联潜在能够对比或含有PTB的受试者的表型和遗传特征。在受MAP感染的牛群中，ELISA,IFN-γ试验，qPCR,在随访中进行了培养，发生在三到六年内，评估个体感染状态。对于至少一个测试测试为阳性的动物被认为是感染的。112头牛的DNA样本,在已知的MAP状态下，进行了分析，以验证与编码γ-干扰素（BoIFNG）的基因中的SNP的关联，白细胞介素受体10（IL10RA），白细胞介素受体12（IL12RB2），和toll样受体(TLR1、TLR2、TLR4)。关于统计分析，在分析的动物组中，目标基因和等位基因对之间的差异，在P<0.05的显著性水平下进行评估。对于IL10RA和IL12RB2基因，观察到考虑的牛组之间基因型频率的相关差异。对于这项调查中研究的所有候选基因，已经与PTB抗性相关的SNP基因型在我们的人群中更常见，暗示了Marchigiana品种的潜在抗性特征。
