Alfano Flora, Peletto Simone, Lucibelli Maria Gabriella, Borriello Giorgia, Urciuolo Giovanna, Maniaci Maria Grazia, Desiato Rosanna, Tarantino Michela, Barone Amalia, Pasquali Paolo, Acutis Pier Luigi, Galiero Giorgio
Istituto Zooprofilattico Sperimentale del Mezzogiorno, Via Salute, 2, 80055, Portici, Italy.
Istituto Zooprofilattico Sperimentale del Piemonte Liguria e Valle d'Aosta, Via Bologna, 148, 10154, Torino, Italy.
BMC Genet. 2014 Dec 14;15:139. doi: 10.1186/s12863-014-0139-y.
Toll-like receptors play a key role in innate immunity by recognizing pathogens and activating appropriate responses. Pathogens express several signal molecules (pathogen-associated molecular patterns, PAMPs) essential for survival and pathogenicity. Recognition of PAMPs triggers an array of anti-microbial immune responses through the induction of various inflammatory cytokines. The objective of this work was to perform a case-control study to characterize the distribution of polymorphisms in three candidate genes (toll-like receptor 2, toll-like receptor 4, toll-like receptor 9) and to test their role as potential risk factors for tuberculosis infection in water buffalo (Bubalus bubalis).
The case-control study included 184 subjects, 59 of which resulted positive to both intradermal TB test and Mycobacterium bovis isolation (cases) and 125 resulted negative to at least three consecutive intradermal TB tests. The statistical analysis indicated that two polymorphisms exhibited significant differences in allelic frequencies between cases and controls. Indeed, the TT genotype at TLR9 2340 C > T locus resulted significantly associated with susceptibility to bovine tuberculosis (P = 0.030, OR = 3.31, 95% CI = 1.05-10.40). One polymorphism resulted significantly associated with resistance to the disease, and included the CC genotype, at the TLR4 672 A > C locus (P = 0.01, OR = 0.26, 95% CI = 0.08-0.80). Haplotype reconstruction of the TLR2 gene revealed one haplotype (CTTACCAGCGGCCAGTCCC) associated with disease resistance (P = 0.04, OR = 0.51, 95% CI = 0.27-0.96), including the allelic variant associated with disease resistance.
The work describes novel mutations in bubaline TLR2, TLR4 and TLR9 genes and presents their association with M. bovis infection. These results will enhance our ability to determine the risk of developing the disease by improving the knowledge of the immune mechanisms involved in host response to mycobacterial infection, and will allow the creation of multiple layers of disease resistance in herds by selective breeding.
Toll样受体通过识别病原体并激活适当反应,在固有免疫中发挥关键作用。病原体表达几种对生存和致病性至关重要的信号分子(病原体相关分子模式,PAMPs)。对PAMPs的识别通过诱导各种炎性细胞因子触发一系列抗微生物免疫反应。本研究的目的是进行一项病例对照研究,以表征三个候选基因(Toll样受体2、Toll样受体4、Toll样受体9)中多态性的分布,并测试它们作为水牛(Bubalus bubalis)结核病感染潜在危险因素的作用。
病例对照研究包括184名受试者,其中59名皮内结核菌素试验和牛分枝杆菌分离均呈阳性(病例组),125名至少连续三次皮内结核菌素试验呈阴性。统计分析表明,两个多态性在病例组和对照组之间的等位基因频率上表现出显著差异。事实上,TLR9 2340 C>T位点的TT基因型与牛结核病易感性显著相关(P = 0.030,OR = 3.31,95%CI = 1.05 - 10.40)。一个多态性与疾病抗性显著相关,包括TLR4 672 A>C位点的CC基因型(P = 0.01,OR = 0.26,95%CI = 0.08 - 0.80)。TLR2基因的单倍型重建显示一个与疾病抗性相关的单倍型(CTTACCAGCGGCCAGTCCC)(P = 0.04,OR = 0.51,95%CI = 0.27 - 0.96),包括与疾病抗性相关的等位基因变体。
该研究描述了水牛TLR2、TLR4和TLR9基因中的新突变,并呈现了它们与牛分枝杆菌感染的关联。这些结果将通过增进对宿主对分枝杆菌感染反应中免疫机制的了解,提高我们确定发病风险的能力,并将通过选择性育种在畜群中建立多层疾病抗性。