The replicase protein nsp2 of Chinese highly pathogenic porcine reproductive and respiratory virus is involved in protective immunity by promoting viral clearance  

作　　者：Can Kong Dan Li Yanxin Hu Peng Gao Yongning Zhang Lei Zhou Xinna Ge Xin Guo Jun Han Hanchun Yang 

机构地区：[1]National Key Laboratory of Veterinary Public Health and Safety,and Key Laboratory of Animal Epidemiology of the Ministry of Agriculture and Rural Affairs,College of Veterinary Medicine,China Agricultural University,Beijing 100193,China

出　　处：《One Health Advances》2023年第1期78-93,共16页全健康进展（英文）

基　　金：supported by the National Natural Science Foundation of China(32025035);China Agriculture Research System of MOF and MARA(CARS-35).

摘　　要：The genome segment for replicase protein nsp2 represents the fastest evolving region of porcine reproductive and respiratory syndrome virus(PRRSV),and our previous studies have shown that the PRRSV nsp2 genetic variation contributes to poor cross-neutralization.By using in vitro antibody absorption assay,here we show that the papainlike protease 2(PLP2)domain of nsp2 is a target of neutralizing antibodies.This was further verified by cross-neutralization assay with a series of inter-lineage chimeric mutants between the Chinese highly pathogenic PRRSV(HP-PRRSV)strain JXwn06 and the low virulent NADC30-like strain CHsx1401(lineage 1).The role of nsp2 in protective immunity was subsequently tested in a one-month SPF piglet model by immunizing the piglets with CHsx1401 or its derivatives carrying JXwn06 structural protein region(SP)alone(CHsx1401-SPJX)or in combination with PLP2 region(CHsx1401-SPplp2JX),or the whole nsp2 region(CHsx1401-SPnsp2JX),followed by challenge with JXwn06 at 42 days post immunization,a time point when the viremia was undetectable.All chimera groups were protected from the challenge by JXwn06,whereas the group CHsx1401 failed to provide beneficial protection.Interestingly,the group CHsx1401-SPnsp2JX,but not CHsx1401-SPplp2JX,showed the lowest lung microscopic lesions and viral tissue load.Significantly,the vaccine virus CHsx1401-SPnsp2JX was undetectable in the examined tissues,and so was for the challenge virus except for one piglet,highlighting an important role of HP-PRRSV nsp2 in promoting viral clearance.The findings provide insight into the mechanisms underlying the protective immunity against PRRSV and have important implications in PRRSV vaccine development.

关 键 词：PRRSV NSP2 Protective immunity 

分 类 号：S85[农业科学—兽医学]