CAJ | 학술논문

为了解连续免疫压力下猪繁殖与呼吸综合征病毒（PRRSV）的变异规律，以及为猪繁殖与呼吸综合征病的防控提供科学依据，以贵州分离株 PRRSV AS 为研究对象，监测分析了 PRRSV 接种免疫猪群后其主要基因变异情况。结果表明：1）接种 PRRSV 后，免疫猪只未发生死亡现象，但出现轻微的临床表现和病理变化，且能在病变组织中分离到 PRRSV，并扩增出与预期大小相一致的 Nsp2和 GP5基因条带；2）对Nsp2基因，两次分离物 PRRSV AS-a、PRRSV AS-b 与原始病毒 PRRSV AS 的遗传距离相应为0．018和0．064，呈加速渐远趋势；PRRSV AS-a 发生16处点突变，其中9处为非同义突变，7处为同义突变；PRRSV AS-b 发生25处点突变，其中非同义突变12处，同义突变13处；从 PRRSV AS 向 PRRSV AS-a 到PRRSV AS-b 演变过程中，Nsp2基因编码蛋白第285～293位抗原指数发生不同程度改变，且演变趋势呈正向选择作用；3）对 GP5基因，两次分离物 PRRSV AS-a、PRRSV AS-b 与原始病毒 PRRSV AS 的遗传距离相应为0．004和0．015，变异趋势不明显；PRRSV AS-a 发生2处点突变，非同义突变和同义突变各1处；PRRSV AS-b 发生3处点突变，其中非同义突变2处，同义突变1处；从 PRRSV AS 向 PRRSV AS-a 到PRRSV AS-b 演变过程中，GP5基因编码蛋白重要抗原表位未发生改变，但其演变呈正向选择作用。说明，在连续免疫压力下 PRRSV 容易发生变异。
위료해련속면역압력하저번식여호흡종합정병독（PRRSV）적변이규률，이급위저번식여호흡종합정병적방공제공과학의거，이귀주분리주 PRRSV AS 위연구대상，감측분석료 PRRSV 접충면역저군후기주요기인변이정황。결과표명：1）접충 PRRSV 후，면역저지미발생사망현상，단출현경미적림상표현화병리변화，차능재병변조직중분리도 PRRSV，병확증출여예기대소상일치적 Nsp2화 GP5기인조대；2）대Nsp2기인，량차분리물 PRRSV AS-a、PRRSV AS-b 여원시병독 PRRSV AS 적유전거리상응위0．018화0．064，정가속점원추세；PRRSV AS-a 발생16처점돌변，기중9처위비동의돌변，7처위동의돌변；PRRSV AS-b 발생25처점돌변，기중비동의돌변12처，동의돌변13처；종 PRRSV AS 향 PRRSV AS-a 도PRRSV AS-b 연변과정중，Nsp2기인편마단백제285～293위항원지수발생불동정도개변，차연변추세정정향선택작용；3）대 GP5기인，량차분리물 PRRSV AS-a、PRRSV AS-b 여원시병독 PRRSV AS 적유전거리상응위0．004화0．015，변이추세불명현；PRRSV AS-a 발생2처점돌변，비동의돌변화동의돌변각1처；PRRSV AS-b 발생3처점돌변，기중비동의돌변2처，동의돌변1처；종 PRRSV AS 향 PRRSV AS-a 도PRRSV AS-b 연변과정중，GP5기인편마단백중요항원표위미발생개변，단기연변정정향선택작용。설명，재련속면역압력하 PRRSV 용역발생변이。
Main gene variation of pigs inoculated with PRRSV AS (Guizhou PRRSV strain)was analyzed to study PRRSV variation pattern under the continuous immune stress for PRRS prevention and control.The results showed that:1)The immune pigs with slight clinical manifestation and pathological change do not die and the expected Nsp2 and GP5 gene bands can be amplified from PRRSV of diseased tissues;2)The genetic distance between original virus and PRRSV AS-a,PRRSV AS-b is 0.018 and 0. 064 in Nsp2 gene respectively.There are 16 point mutations including 9 non-synonymous mutations and 7 synonymous mutations in PRRSV AS-a. There are 25 point mutations including12 non-synonymous mutations and 13 synonymous mutations in PRRSV AS-b.285aa~ 293aa antigen indexes of Nsp2 gene coding protein change to varying degree during the evolution process of PRRSV AS from PRRSV AS-a to PRRSV AS-b and the evolution trend presents the positive selection role;3)The genetic distance between original virus and PRRSV AS-a,PRRSV AS-b is 0.004 and 0.015 in GP5 gene respectively.There are 2 point mutations including one non-synonymous mutation and one synonymous mutation in PRRSV AS-a. There are three point mutations including two non-synonymous mutations and one synonymous mutation in PRRSV AS-b.The important antigenic epitope of GP5 gene coding protein does not change during the evolution process of PRRSV AS from PRRSV AS-a to PRRSV AS-b and the evolution trend presents the positive selection role.In conclusion,PRRSV occurs variation under the continuous immune stress easily.