Malek Massoud, Lamont Susan J
Department of Animal Science, Iowa State University, 2255 Kildee Hall, Ames, IA 50011-3150, USA.
Genet Sel Evol. 2003;35 Suppl 1(Suppl 1):S99-111. doi: 10.1186/1297-9686-35-s1-s99.
Several candidate genes were selected, based on their critical roles in the host's response to intracellular bacteria, to study the genetic control of the chicken response to Salmonella enteritidis (SE). The candidate genes were: inducible nitric oxide synthase (INOS), tumor necrosis factor related apoptosis inducing ligand (TRAIL), transforming growth factor beta2 (TGF-beta2), transforming growth factor beta3 (TGF-beta3), and immunoglobulin G light chain (IgL). Responses to pathogenic SE colonization or to SE vaccination were measured in the Iowa Salmonella response resource population (ISRRP). Outbred broiler sires and three diverse, highly inbred dam lines produced 508 F1 progeny, which were evaluated as young chicks for either bacterial load isolated from spleen or cecum contents after pathogenic SE inoculation, or the circulating antibody level after SE vaccination. Fragments of each gene were sequenced from the founder lines of the resource population to identify genomic sequence variation. Single nucleotide polymorphisms (SNP) were identified, then PCR-RFLP techniques were developed to genotype the F1 resource population. Linear mixed models were used for statistical analyses. Because the inbred dam lines always contributed one copy of the same allele, the heterozygous sire allele effects could be assessed in the F1 generation. Association analyses revealed significant effects of the sire allele of TRAIL-StyI on the spleen (P <0.07) and cecum (P <0.0002) SE bacterial load. Significant effects (P <0.04) were found on the cecum bacterial load for TGF-beta3-BsrI. Varied and moderate association was found for SE vaccine antibody response for all genes. This is the first reported study on the association of SNP in INOS, TRAIL, TGF-beta2, TGF-beta3, and IgL with the chicken response to SE. Identification of candidate genes to improve the immune response may be useful for marker-assisted selection to enhance disease resistance.
基于几个候选基因在宿主对细胞内细菌反应中的关键作用，选择它们来研究鸡对肠炎沙门氏菌（SE）反应的遗传控制。候选基因包括：诱导型一氧化氮合酶（INOS）、肿瘤坏死因子相关凋亡诱导配体（TRAIL）、转化生长因子β2（TGF-β2）、转化生长因子β3（TGF-β3）和免疫球蛋白G轻链（IgL）。在爱荷华沙门氏菌反应资源群体（ISRRP）中测量了对致病性SE定植或SE疫苗接种的反应。远交肉鸡父本和三个不同的、高度近交的母本系产生了508只F1后代，这些后代作为幼雏进行评估，评估内容为致病性SE接种后从脾脏或盲肠内容物中分离出的细菌载量，或SE疫苗接种后的循环抗体水平。从资源群体的奠基系中对每个基因的片段进行测序，以鉴定基因组序列变异。鉴定出单核苷酸多态性（SNP），然后开发PCR-RFLP技术对F1资源群体进行基因分型。使用线性混合模型进行统计分析。由于近交母本系总是贡献相同等位基因的一个拷贝，因此可以在F1代中评估杂合父本等位基因的效应。关联分析显示，TRAIL-StyI的父本等位基因对脾脏（P<0.07）和盲肠（P<0.0002）的SE细菌载量有显著影响。发现TGF-β3-BsrI对盲肠细菌载量有显著影响（P<0.04）。发现所有基因对SE疫苗抗体反应有不同程度的中等关联。这是首次报道的关于INOS、TRAIL、TGF-β2、TGF-β3和IgL中的SNP与鸡对SE反应的关联研究。鉴定改善免疫反应的候选基因可能有助于标记辅助选择以增强抗病性。
