绵羊肺腺瘤病毒内蒙古分离株前病毒全基因组克隆及序列分析北大核心CSCD

为了探究绵羊肺腺瘤病毒(Jaagsiekte sheep retrovirus,JSRV)内蒙古流行株与国际各代表株间的亲缘关系,本研究以内蒙古地区绵羊肺腺瘤病自然病例的肺组织总DNA为模板,克隆gag、pro与pol基因,并应用双酶切的方法将其与本实验室先期制备并保存的LTR、env基因连接起来,得到了含有JSRV内蒙古分离株前病毒全基因组重组质粒pMD-JSRV。序列分析结果表明,JSRV内蒙古分离株前病毒全基因组全长7 690bp,具外源性JSRV典型的分子特征:1在gag基因中含Sca I酶切位点;2核衣壳蛋白区有2个保守的可形成锌指结构的"CCHC"基序;3env基因编码的TM区胞浆尾部包含保守的特异性"YXXM"基序。将其进行同源性分析,结果表明该株病毒属JSRV-II型,与分离自美国的代表株AF105220间亲缘关系较近,同源性达95%。本研究为进一步探讨JSRV内蒙古分离株基因组结构特点与其致病机制间的关系奠定了基础。     

绵羊肺腺瘤病毒内蒙古分离株前病毒全基因组克隆及序列分析

为了探究绵羊肺腺瘤病毒(Jaagsiekte sheep retrovirus,JSRV)内蒙古流行株与国际各代表株间的亲缘关系,本研究以内蒙古地区绵羊肺腺瘤病自然病例的肺组织总DNA为模板,克隆gag、pro与pol基因,并应用双酶切的方法将其与本实验室先期制备并保存的LTR、env基因连接起来,得到了含有JSRV内蒙古分离株前病毒全基因组重组质粒pMD-JSRV。序列分析结果表明,JSRV内蒙古分离株前病毒全基因组全长7 690bp,具外源性JSRV典型的分子特征:1在gag基因中含Sca I酶切位点;2核衣壳蛋白区有2个保守的可形成锌指结构的"CCHC"基序;3env基因编码的TM区胞浆尾部包含保守的特异性"YXXM"基序。将其进行同源性分析,结果表明该株病毒属JSRV-II型,与分离自美国的代表株AF105220间亲缘关系较近,同源性达95%。本研究为进一步探讨JSRV内蒙古分离株基因组结构特点与其致病机制间的关系奠定了基础。     

绵羊肺腺瘤病毒NM株前病毒基因组的克隆与全序列分析

本研究参照GenBank中已发表的绵羊肺腺瘤病毒的基因组全序列,设计合成8对引物,从内蒙古某羊场自然感染绵羊肺腺瘤病的病肺肿瘤组织中提取总DNA为模板,对JSRV-NM株基因组分8段进行PCR扩增,产物分别为8个(531bp,888bp,949bp,944bp,1428bp,947bp,1836bp,538bp)基因片段,将其分别克隆入pMD-18T载体中进行双向测序并拼接序列,获得完整的JSRV-NM株前病毒基因组全序列。结果表明,JSRV-NM株前病毒基因组全长7430bp,有相互重叠的4个较长的开放阅读框(ORF),分别代表gag、pro、pol和env基因。与绵羊肺腺瘤病毒Ⅰ型即南非代表株(NC-001494)和绵羊肺腺瘤病毒Ⅱ型即美国代表株(AF105220)的核苷酸同源性比较分别为90.4%和90%,推导出的氨基酸同源性分别为90%和89.1%。分析JSRV-NM株基因组结构,发现在LTR的上游和下游都具有外源性exJSRV特有的ScaⅠ酶切位点,在gag基因编码的NC区发现有2个较典型的“胱氨酸—组氨酸序列”,可形成锌指结构。在env基因编码的TM区有特异性的“YXXM”基序。用地高辛标记外源性exJSRV特异的JSRV-2片段制成探针,原位杂交法检测自然感染绵羊肺腺瘤病(OPA)的病肺组织中JSRV-NM的RNA及前病毒DNA,结果表明OPA患羊肺肿瘤细胞的胞浆和核内都有JSRV-2基因mRNA的表达,说明JSRV-NM株是具有致瘤作用的外源性反转录病毒。这是我国首次报道的绵羊肺腺瘤病毒的基因组全序列。     

绵羊肺腺瘤病毒NM株前病毒基因组的克隆与全序列分析

本研究参照GenBank中已发表的绵羊肺腺瘤病毒的基因组全序列,设计合成8对引物,从内蒙古某羊场自然感染绵羊肺腺瘤病的病肺肿瘤组织中提取总DNA为模板,对JSRV-NM株基因组分8段进行PCR扩增,产物分别为8个(531bp, 888bp, 949 bp, 944bp, 1428bp, 947bp, 1836bp, 538bp)基因片段,将其分别克隆入pMD-18 T载体中进行双向测序并拼接序列,获得完整的JSRV-NM株前病毒基因组全序列.结果表明,JSRV-NM株前病毒基因组全长7430bp,有相互重叠的4个较长的开放阅读框(ORF),分别代表gag、 pro、 pol 和 env基因.与绵羊肺腺瘤病毒Ⅰ型即南非代表株(NC-001494)和绵羊肺腺瘤病毒Ⅱ型即美国代表株(AF105220)的核苷酸同源性比较分别为90.4%和90%,推导出的氨基酸同源性分别为90%和89.1%.分析JSRV-NM株基因组结构,发现在LTR的上游和下游都具有外源性exJSRV特有的ScaⅠ酶切位点,在gag基因编码的NC区发现有2个较典型的"胱氨酸-组氨酸序列",可形成锌指结构.在env基因编码的TM区有特异性的"YXXM"基序.用地高辛标记外源性exJSRV特异的JSRV-2片段制成探针,原位杂交法检测自然感染绵羊肺腺瘤病(OPA)的病肺组织中JSRV-NM的 RNA及前病毒DNA,结果表明OPA患羊肺肿瘤细胞的胞浆和核内都有JSRV-2基因mRNA的表达, 说明JSRV-NM株是具有致瘤作用的外源性反转录病毒.这是我国首次报道的绵羊肺腺瘤病毒的基因组全序列.     

西部马脑炎病毒基因组序列的半套式RT-PCR检测

为进一步提高RT－PCR检测西部马脑炎病毒（WEE）病毒基因组方法的敏感性,采用半套式PCR扩增病毒基因组特异序列,首先采用逆转录法将病毒基因组RNA逆转录为cDNA,然后以此cDNA为模板,进行扩增。对扩增后电泳检查无可见DNA条带的产物进行半套式PCR;与此同时对扩增的循环数、Mg^ 浓度和退火温度等条件进行了优化,以进一步提高扩增的特异性。结果第一轮PCR未扩出特异笥片段的WEE病毒稀释度,其半套式扩增出特定大小的DNA产物;同时优化的条件提高了扩增产物的特异性。扩增产物约为190bp的单一DNA片段,其大小与预期的相一致,结果表明采用半套式RT－PCR方法检测WEE病毒的基因组序列的敏感性可提高100倍以上。     

新疆绵羊肺腺瘤病理学诊断与全基因组序列分析

为了完成新疆绵羊肺腺瘤病毒诊断及全基因组序列测定,本研究采用兽医临床病理学和组织病理学观察疑似患病羊,并提取病毒悬液进行透射电镜观察,从患病绵羊的肺脏组织中提取基因RNA反转录为cDNA。参照GenBank中外源性绵羊肺腺瘤病毒美国株基因序列(AF105220)设计六对引物,对病料样品进行RT-PCR扩增和测序分析。结果表明,"小推车试验"时有鼻液流出,显微镜下观察,患病羊的肺脏有大小不一的腺瘤灶,且肺泡上皮细胞呈乳头状增生,肺泡腔内充满巨噬细胞,病灶中央的细胞核溶解。透射电镜观察到病毒颗粒直径大小约为88nm~125.4nm。RT-PCR扩增病毒基因组片段,获得完整的基因组序列全长7 456bp。与美国代表株(AF105220)和英国代表株(AF357971)BLAST在线比对核苷酸同源性结果分别为96%和95%,与内源性绵羊肺腺瘤病毒(enJSRV)内蒙株(DQ838493)和美国株(EF680300)的核苷酸同源性分别为89.8%和89.9%。获得的全基因组序列的TM区的氨基酸序列中具有外源性绵羊肺腺瘤病毒(exJSRV)特有的致病性"YXXM"序列。说明此基因序列具有致瘤作用,这是我国新疆首次报道的外源性绵羊肺腺瘤病毒的全基因组序列,为更深入的研究新疆绵羊肺腺瘤病毒的生物学特性和致病机理奠定基础。     

PCR技术在猴免疫缺陷病毒(SIV)感染模型中的应用

目的(1)建立RT PCR方法,定性测定SIV感染猴血浆中病毒RNA,比较其与传统血浆病毒分离方法的敏感性;(2)建立DNA PCR方法,检测SIV感染猴外周血淋巴细胞(PBMCs)中的前病毒DNA。(3)检验DNA PCR和RNA PCR方法在猴SAIDS模型应用中的实用性和可操作性。方法用SIVmac251静脉感染恒河猴,定期采血,从血浆中提取病毒RNA,以RNA为模板通过RT PCR法扩增,凝胶电泳定性;从感染猴PBMC中提取带有整合的SIV前病毒DNA的细胞基因组DNA,巢式PCR扩增,凝胶电泳定性。结果DNA PCR和RNA PCR经两轮扩增后均得到一长度为477bp的特异条带,测序鉴定确为目的片段。9只实验猴感染SIV后7d,RNA PCR结果为79阳性,DNA PCR结果为100%阳性,而血浆病毒分离只有59阳性;此后一直到感染后的42d,RNA PCR和DNA PCR的结果一直为100%阳性,而血浆病毒分离阳性率在感染后35d下降到49,到42d时下降为零。结论PCR方法比病毒分离方法的敏感性高。尤其是DNA PCR,既可检测具有活跃病毒复制的受感染细胞,又可检测那些携带病毒处于转录休眠期的细胞,所以在感染的早期和中后期———血浆病毒水平较低的情况下或病毒处于潜伏感染的阶段,它作为猴艾滋病(SAIDS)模型病毒学指标之一有其必要性和重要性。这个指标的检测方法应该是较血浆病毒RNA检测更为敏感。     

运用套式PCR检测传染性喉气管炎病毒核酸

选择鸡传染性喉气管炎病毒保守TK基因的蛋白编码区域,设计并合成了一对外引物和一对内引物,建立并优化了检测鸡传染性喉气管炎病毒DNA的套式PCR法.通过检测ILTV感染的鸡胚绒毛尿囊膜、实验室病料和临床病料,结果表明,套式PCR法能检测出ILTV感染后的非免疫鸡胚和SPF鸡胚绒毛尿囊膜研磨液中的被稀释了105倍的病毒(约1fg的ILTVDNA),攻毒后第10天还能从非免疫鸡和SPF鸡气管拭子中检出ILTV,第10天非免疫鸡气管拭子中ILTV的最大检出率为7/10,第10天SPF鸡气管拭子中ILTV的最大检出率为8/10.对非免疫鸡和SPF鸡的气管拭子中ILTV最佳检出时间均在攻毒后第5天.对临床样品中的ILTV的最大检出率为7/7.经过核酸杂交验证,套式PCR法具有很高的特异性和敏感性,为从分子水平探讨ILTV的发病机理、临床早期快速诊断提供了新的研究手段.     

运用套式PCR检测传染性喉气管炎病毒核酸

选择鸡传染性喉气管炎病毒保守TK基因的蛋白编码区域,设计并合成了一对外引物和一对内引物,建立并优化了检测鸡传染性喉气管炎病毒DNA的套式PCR法。通过检测ILTV感染的鸡胚绒毛尿囊膜,实验室病料和临床病料,结果表明,套式PCR法能检测出ILTV感染后的非免疫鸡胚和SPF鸡绒毛膜研磨液中的被稀释了10^5倍的病毒（约1fg的ILTV DNA）,攻毒后第10天还能从非免疫鸡和SPF鸡气管拭子中检出ILTV,第10天非免疫鸡气管拭子中ILTV的最大检出率为7／10,第10天SPF鸡气管拭子中ILTV的最大检出率为8／10。对非免疫鸡和SPF鸡的气管拭中ILTV最佳检出时间均在攻毒后第5天。对临床样品中的ILTV的最大检出率为7／7。经过核酸杂交验证,套式PCR法具有很高的特异性和敏感性,为从分子水平探讨ILTV的发病机理、临床早期快速诊断提供了新的研究手段。     

嗜肺军团菌实时荧光定量PCR快速检测方法的建立

目的：建立针对嗜肺军团菌Mip基因的实时荧光定量TaqMan PCR检测方法,并进行自来水和空调冷却水模拟标本的检测评价。方法：根据嗜肺军团菌Mip基因的特异性序列设计引物和TaqMan探针,建立嗜肺军团菌的实时荧光定量TaqMan PCR快速检测方法,对方法进行灵敏度及特异性评价,并对自来水和空调冷却水模拟标本中的嗜肺军团菌进行检测。结果：建立的方法对嗜肺军团菌的检测具有高度特异性,与3种非嗜肺军团菌和6种其他呼吸道病原均没有交叉反应;基因组DNA的检测灵敏度为1.6pg／μL,模拟自来水和空调冷却水标本的检测灵敏度为10CFU／mL。结论：建立的TaqMan荧光定量PCR方法特异、灵敏、快速,适于嗜肺军团菌的日常监测和暴发疫情的应急诊断。     

Receptor usage and fetal expression of ovine endogenous betaretroviruses: implications for coevolution of endogenous and exogenous retroviruses

Betaretroviruses of sheep include two exogenous viruses, Jaagsiekte sheep retrovirus (JSRV) and enzootic nasal tumor virus (ENTV), and a group of endogenous viruses known as enJSRVs. The exogenous JSRV and ENTV are the etiological agents of ovine pulmonary adenocarcinoma (OPA) and enzootic nasal tumor (ENT), respectively. Sheep affected by OPA or ENT do not show an appreciable antibody response to JSRV or ENTV. Consequently, it is conceivable that enJSRV expression in the fetal lamb tolerizes sheep to the related exogenous viruses. In this study, possible mechanisms of interference between the sheep exogenous and endogenous betaretroviruses were investigated. In situ hybridization detected enJSRV RNAs in lymphoid cells associated with the lamina propria of the small intestine and in the thymus of sheep fetuses. Low-level expression of enJSRVs was also detected in the lungs. In addition, expression of enJSRVs was found to block entry of the exogenous JSRV, presumably via mechanisms of receptor interference. Indeed, enJSRVs, like JSRV and ENTV, were found to utilize hyaluronidase-2 as a cellular receptor.     

Lung adenocarcinoma originates from retrovirus infection of proliferating type 2 pneumocytes during pulmonary post-natal development or tissue repair

Jaagsiekte sheep retrovirus (JSRV) is a unique oncogenic virus with distinctive biological properties. JSRV is the only virus causing a naturally occurring lung cancer (ovine pulmonary adenocarcinoma, OPA) and possessing a major structural protein that functions as a dominant oncoprotein. Lung cancer is the major cause of death among cancer patients. OPA can be an extremely useful animal model in order to identify the cells originating lung adenocarcinoma and to study the early events of pulmonary carcinogenesis. In this study, we demonstrated that lung adenocarcinoma in sheep originates from infection and transformation of proliferating type 2 pneumocytes (termed here lung alveolar proliferating cells, LAPCs). We excluded that OPA originates from a bronchioalveolar stem cell, or from mature post-mitotic type 2 pneumocytes or from either proliferating or non-proliferating Clara cells. We show that young animals possess abundant LAPCs and are highly susceptible to JSRV infection and transformation. On the contrary, healthy adult sheep, which are normally resistant to experimental OPA induction, exhibit a relatively low number of LAPCs and are resistant to JSRV infection of the respiratory epithelium. Importantly, induction of lung injury increased dramatically the number of LAPCs in adult sheep and rendered these animals fully susceptible to JSRV infection and transformation. Furthermore, we show that JSRV preferentially infects actively dividing cell in vitro. Overall, our study provides unique insights into pulmonary biology and carcinogenesis and suggests that JSRV and its host have reached an evolutionary equilibrium in which productive infection (and transformation) can occur only in cells that are scarce for most of the lifespan of the sheep. Our data also indicate that, at least in this model, inflammation can predispose to retroviral infection and cancer.     

Jaagsiekte sheep retrovirus infects multiple cell types in the ovine lung

Ovine pulmonary adenocarcinoma (OPA) is a transmissible lung cancer of sheep caused by Jaagsiekte sheep retrovirus (JSRV). The details of early events in the pathogenesis of OPA are not fully understood. For example, the identity of the JSRV target cell in the lung has not yet been determined. Mature OPA tumors express surfactant protein-C (SP-C) or Clara cell-specific protein (CCSP), which are specific markers of type II pneumocytes or Clara cells, respectively. However, it is unclear whether these are the cell types initially infected and transformed by JSRV or whether the virus targets stem cells in the lung that subsequently acquire a differentiated phenotype during tumor growth. To examine this question, JSRV-infected lung tissue from experimentally infected lambs was studied at early time points after infection. Single JSRV-infected cells were detectable 10 days postinfection in bronchiolar and alveolar regions. These infected cells were labeled with anti-SP-C or anti-CCSP antibodies, indicating that differentiated epithelial cells are early targets for JSRV infection in the ovine lung. In addition, undifferentiated cells that expressed neither SP-C nor CCSP were also found to express the JSRV Env protein. These results enhance the understanding of OPA pathogenesis and may have comparative relevance to human lung cancer, for which samples representing early stages of tumor growth are difficult to obtain.     

Expression of the jaagsiekte sheep retrovirus envelope glycoprotein is sufficient to induce lung tumors in sheep

Jaagsiekte sheep retrovirus (JSRV) is the causative agent of ovine pulmonary adenocarcinoma (OPA). The expression of the JSRV envelope (Env) alone is sufficient to transform a variety of cell lines in vitro and induce lung cancer in immunodeficient mice. In order to determine the role of the JSRV Env in OPA tumorigenesis in sheep, we derived a JSRV replication-defective virus (JS-RD) which expresses env under the control of its own long terminal repeat (LTR). JS-RD was produced by transiently transfecting 293T cells with a two plasmid system, involving (i) a packaging plasmid, with the putative JSRV packaging signal deleted, expressing the structural and enzymatic proteins Gag, Pro, and Pol, and (ii) a plasmid which expresses env in trans for JS-RD particles and provides the genomes necessary to deliver JSRV env upon infection. During the optimization of the JS-RD system we determined that both R-U5 (in the viral 5' LTR) and the env region are important for JSRV particle production. Two independent experimental transmission studies were carried out with newborn lambs. Four of five lambs inoculated with JS-RD showed OPA lesions in the lungs at various times between 4 and 12 months postinoculation. Abundant expression of JSRV Env was detected in tumor cells of JS-RD-infected animals and PCR assays confirmed the presence of the deleted JS-RD genome. These data strongly suggest that the JSRV Env functions as a dominant oncoprotein in the natural immunocompetent host and that JSRV can induce OPA in the absence of viral spread.     

Ovine pulmonary adenocarcinoma as an animal model of progressive lung cancer and the impact of nutritional selenium supply

Jaagsiekte sheep retrovirus (JSRV) is known to induce ovine pulmonary adenocarcinoma (OPA). Several studies have suggested an influence of selenium (Se) status on cancer progression. Thus, combining OPA with a defined Se supply might serve as a suitable animal model to study the impact of Se on lung cancer progression.16 naturally JSRV-infected sheep were divided into 2 treatment groups receiving (a) <0.05 and (b) 0.2 mg Se/kg dry matter in diet, respectively. Computed tomography (CT) was performed repeatedly and evaluated using a CT-OPA-score system. Liver biopsies were taken three-monthly, blood samples were collected biweekly to study treatment effects on Se concentrations and glutathione peroxidase (GPx) activity. Cell pellets from bronchoalveolar lavage fluid (BALF) were tested for JSRV by PCR to approve the infection. To date, four animals of the ongoing study have been euthanised. Autopsy and histopathology were performed and correlated to CT analysis.JSRV was detected in BALF cell pellets. Progression of lung tumours was monitored successfully by repeated CT examinations, enabling the detection of even small nodules or increased lung density. Histopathology revealed bronchioloalveolar adenocarcinoma in lung areas suspicious to be OPA from CT evaluation. Score-based analysis of CT images for quantifying tumour progression proved as a valuable tool.Se concentration and GPx activity increased in liver and serum of group b and verified the efficiency of different feeding regime.In conclusion, OPA along with CT, autopsy/histopathology, trace element and enzyme activity analysis provide a suitable large animal model to examine the impact of Se supply on lung tumourigenesis.     

Analysis of integration sites of Jaagsiekte sheep retrovirus in ovine pulmonary adenocarcinoma

Ovine pulmonary adenocarcinoma (OPA) is an infectious lung tumor of sheep caused by Jaagsiekte sheep retrovirus (JSRV). To test the hypothesis that JSRV insertional mutagenesis is involved in the oncogenesis of OPA, we cloned and characterized 70 independent integration sites from 23 cases of OPA. Multiple integration sites were identified in most tumors. BLAST analysis of the sequences did not disclose any potential oncogenic motifs or any identical integration sites in different tumors. Thirty-seven of the integration sites were mapped to individual chromosomes by PCR with a panel of sheep-hamster hybrid cell lines. Integration sites were found on 20 of the 28 sheep chromosomes, suggesting a random distribution. However, four integration sites from four different tumors mapped to chromosome 16. By Southern blot hybridization, probes derived from two of these sites mapped to within 5 kb of each other on normal sheep DNA. These sites were found within a single sheep bacterial artificial chromosome clone and were further mapped to only 2.5 kb apart, within an uncharacterized predicted gene and less than 200 kb from a mitogen-activated protein kinase-encoding gene. These findings suggest that there is at least one common integration site for JSRV in OPA and add weight to the hypothesis that insertional mutagenesis is involved in the development of this tumor.     

Jaagsiekte sheep retrovirus Env protein stabilizes retrovirus vectors against inactivation by lung surfactant, centrifugation, and freeze-thaw cycling

Jaagsiekte sheep retrovirus (JSRV) replicates in the lungs of sheep and causes the secretion of copious lung fluid containing the virus. Adaptation of JSRV to infection and replication in the lung and its apparent resistance to the denaturing activity of lung fluid suggest that vectors based on JSRV would be useful for gene therapy targeted to the lung. We show here that a retrovirus vector bearing the JSRV Env is stable during treatment with lung surfactant while an otherwise identical vector bearing an amphotropic Env is inactivated. Furthermore, the JSRV vector was stable during centrifugation, allowing facile vector concentration, and showed no loss of activity after six freeze-thaw cycles. However, the JSRV vector was inactivated by standard disinfectants, indicating that JSRV vectors pose no unusual safety risk related to their improved stability under other conditions.     

Jaagsiekte retrovirus is widely distributed both in T and B lymphocytes and in mononuclear phagocytes of sheep with naturally and experimentally acquired pulmonary adenomatosis

Jaagsiekte sheep retrovirus (JSRV) is a type D retrovirus specifically associated with a contagious lung tumor of sheep, sheep pulmonary adenomatosis (SPA). JSRV replicates actively in the transformed epithelial cells of the lung, and JSRV DNA and RNA have been detected in lymphoid tissues of naturally affected animals. To determine the lymphoid target cells of JSRV, CD4(+) T cells, CD8(+) T cells, B lymphocytes, and adherent cell (macrophage/monocyte) populations were isolated from the mediastinal lymph nodes of naturally affected sheep and lambs inoculated with JSRV. Cells were enriched to high purity and then analyzed for JSRV proviral DNA by heminested PCR, and the proviral burden was quantitated by limiting dilution analysis. JSRV proviral DNA was found in all subsets examined but not in appropriate negative controls. In sheep naturally affected with SPA, JSRV proviral burden was greatest in the adherent cell population. In the nonadherent lymphocyte population, surface immunoglobulin-positive B cells contained the greatest proviral burden, while CD4(+) and CD8(+) T cells contained the lowest levels of JSRV proviral DNA. In most of the cases (5 of 8), provirus also could be detected in the peripheral blood mononuclear cell (PBMC) population. A kinetic study of JSRV infection in the mediastinal lymphocyte population of newborn lambs inoculated with JSRV found that JSRV proviral DNA could be detected as early as 7 days postinoculation before the onset of pulmonary adenomatosis, although the proviral burden was greatly reduced compared to adult natural cases. This was reflected in the levels found in PBMC since proviral DNA was detected in 2 of 13 animals. At the early time points studied (7 to 28 days postinoculation) no one subset was preferentially infected. These data indicate that JSRV can infect lymphoid and phagocytic mononuclear cells of sheep and that dissemination precedes tumor formation. Infection of lymphoid tissue, therefore, may play an important role in the pathogenesis of SPA.     

SNPs in candidate genes MX dynamin‐like GTPase and chemokine (C‐C motif) receptor‐5 are associated with ovine pulmonary adenocarcinoma progression in Latxa sheep

Ovine pulmonary adenocarcinoma (OPA) is a contagious lung cancer in sheep caused by Jaagsiekte sheep retrovirus (JSRV). OPA is present in many sheep‐rearing countries causing economic and welfare issues, as currently no efficient vaccines or treatments are available. Breed differences suggest a host genetic component may influence the pathogenesis of OPA, but so far few genes have been identified. In this work, a genetic association study was carried out in Latxa dairy sheep which were classified as cases/controls based on the presence/absence of OPA lung tumours. Candidate genes included cytokines and a receptor and innate immunity genes. After SNPs in the candidate genes were identified, the distribution of alleles in cases and controls was compared by means of logistic regression analyses at the allelic, genotypic and haplotypic levels. The association analysis showed that several candidate genes were significantly associated with resistance or susceptibility to OPA; two of the candidates, CCR5 and MX1, remained significantly associated with resistance and susceptibility respectively, even after Bonferroni correction.