B型流感病毒(influenza B virus,IBV)比A型流感病毒(influenza A virus,IAV)更易引发并发症,在一定季节内造成的疾病负担甚至超过IAV,但目前人们对IBV的关注较少。为了分析IBV临床毒株B/Guangxi-Jiangzhou/1352/2018的遗传进化特点,本...B型流感病毒(influenza B virus,IBV)比A型流感病毒(influenza A virus,IAV)更易引发并发症,在一定季节内造成的疾病负担甚至超过IAV,但目前人们对IBV的关注较少。为了分析IBV临床毒株B/Guangxi-Jiangzhou/1352/2018的遗传进化特点,本研究构建了系统进化树,并以世界卫生组织推荐的疫苗株为参考,对其血凝素(hemagglutinin,HA)和神经氨酸酶(neuraminidase,NA)进行了氨基酸序列同源性及突变位点分析。分析结果发现B/Guangxi-Jiangzhou/1352/2018毒株无谱系间重配现象,与同年疫苗株B/Colorado/06/2017匹配性较差。另外,测定了B/Guangxi-Jiangzhou/1352/2018毒株感染小鼠的半数致死量(median lethal dose,LD_(50))及其对小鼠的致病性。结果表明,B/Guangxi-Jiangzhou/1352/2018毒株感染小鼠的LD_(50)为10^(5.9) TCID_(50)(median tissue culture infective dose),小鼠肺脏中病毒滴度在感染后1 d达到高峰,炎性细胞因子的mRNA水平在感染后12 h达到高峰,且感染后肺脏中的肺泡损伤严重,有大量炎性细胞浸润。本研究证明了IBV临床毒株B/Guangxi-Jiangzhou/1352/2018可以感染小鼠并诱发典型的肺脏炎症,为研究IBV致病及传播机制奠定了基础,为评价新型流感疫苗、抗病毒和抗炎症药物提供了理想的动物模型。展开更多
Infectious bronchitis virus was isolated from swollen proventriculi of clinically ill chicken. The suspected virus samples (2/97, 3/97, 1/98) were adapted in SPF chicken embryos for virus isolation and identification....Infectious bronchitis virus was isolated from swollen proventriculi of clinically ill chicken. The suspected virus samples (2/97, 3/97, 1/98) were adapted in SPF chicken embryos for virus isolation and identification. All the virus isolates were able to agglutinate chicken erythrocytes after treatment with trypsin, and interfer with the reproduction of Newcastle disease virus in chicken embryos, and have low antigenic relat-edness values with reference positive IBV. The isolates 2/97, 3/97, 1/98 RNAs extracted from the allantoic fluid of inoculated embryonated eggs were converted to cDNA by reverse transcription with 3'-primer of S1 gene of (IBV). Polymerase chain reaction (PCR) was performed with two primers which span the S1 gene. Amplified product of 1. 93 kb was subjected to EcoR I and BamH I digestion and the fragments obtained were the same as expected size. The PCR product was ligated to pBlueScript-SK ( + ) vector, and its nucleotide sequence was determined by the dideoxy-mediated chain termination method. Nucleotide sequence analysis showed 73. 6 - 99. 7% homology between the isolated IBV and the IBV strains in GenBank. The homology of amino acid was 71. 4 - 99.4%.展开更多
文摘Infectious bronchitis virus was isolated from swollen proventriculi of clinically ill chicken. The suspected virus samples (2/97, 3/97, 1/98) were adapted in SPF chicken embryos for virus isolation and identification. All the virus isolates were able to agglutinate chicken erythrocytes after treatment with trypsin, and interfer with the reproduction of Newcastle disease virus in chicken embryos, and have low antigenic relat-edness values with reference positive IBV. The isolates 2/97, 3/97, 1/98 RNAs extracted from the allantoic fluid of inoculated embryonated eggs were converted to cDNA by reverse transcription with 3'-primer of S1 gene of (IBV). Polymerase chain reaction (PCR) was performed with two primers which span the S1 gene. Amplified product of 1. 93 kb was subjected to EcoR I and BamH I digestion and the fragments obtained were the same as expected size. The PCR product was ligated to pBlueScript-SK ( + ) vector, and its nucleotide sequence was determined by the dideoxy-mediated chain termination method. Nucleotide sequence analysis showed 73. 6 - 99. 7% homology between the isolated IBV and the IBV strains in GenBank. The homology of amino acid was 71. 4 - 99.4%.
