Calzada-Nova Gabriela, Husmann Robert J, Schnitzlein William M, Zuckermann Federico A
Department of Pathobiology, College of Veterinary Medicine, University of Illinois, 2001 South Lincoln Avenue, Urbana, IL, USA.
Vet Immunol Immunopathol. 2012 Jul 15;148(1-2):116-25. doi: 10.1016/j.vetimm.2012.05.008. Epub 2012 May 11.
The abilities of the modified-live Prime Pac (PP) strain of porcine reproductive and respiratory syndrome virus (PRRSV), propagated in either traditional simian cells (MARC-145) or in a novel porcine alveolar macrophage cell line (ZMAC), to confer pigs protection against subsequent PRRSV challenge were compared. Eight week-old pigs were injected with PP virus grown in one of the two cell types and then exposed 4 weeks later to the "atypical" PRRSV isolate NADC-20. Control animals were similarly challenged or remained PRRSV-naïve. While the average adjusted body weight (aabw) of the strict control group increased 22% by 10 days post challenge (pc), this value for the non-vaccinated, challenged group dropped 4%. In contrast, prior immunization with PP virus, regardless of its host cell source, ameliorated this effect by affording a >9% rise in aabw. Likewise, nearly equivalent protection was extended to both groups of vaccinates in regards to the temporal elimination of their pc clinical distress and viremia. However, the PP virus propagated in ZMAC cells appeared to be more efficacious since four of the six pigs receiving this biologic cleared the challenge virus from the their lungs by 10 days pc as compared to only one member of the other vaccinated group. Notably, the predominant quasispecies in the ZMAC cell-prepared PP virus stock contained a highly conserved N-glycosylation site at position 184 in its glycoprotein 2 while this entity was underrepresented in the MARC-145 cell grown biologic. Since glycoprotein 2 is involved in infectivity, such additional glycosylation may enhance virus replication in porcine alveolar macrophages.
比较了在传统猴细胞（MARC - 145）或新型猪肺泡巨噬细胞系（ZMAC）中繁殖的猪繁殖与呼吸综合征病毒（PRRSV）的改良活疫苗Prime Pac（PP）株赋予猪抵抗后续PRRSV攻击的能力。8周龄的猪注射了在两种细胞类型之一中生长的PP病毒，4周后暴露于“非典型”PRRSV分离株NADC - 20。对照动物同样受到攻击或保持未感染PRRSV的状态。虽然严格对照组的平均调整体重（aabw）在攻击后10天（pc）增加了22%，但未接种疫苗且受到攻击的组该值下降了4%。相比之下，用PP病毒预先免疫，无论其宿主细胞来源如何，通过使aabw升高>9%改善了这种影响。同样，在暂时消除pc临床不适和病毒血症方面，两组接种疫苗的动物都获得了几乎相同的保护。然而，在ZMAC细胞中繁殖的PP病毒似乎更有效，因为接受这种生物制剂的6头猪中有4头在pc后10天从肺部清除了攻击病毒，而另一接种疫苗组只有1头。值得注意的是，ZMAC细胞制备的PP病毒储备中的主要准种在其糖蛋白2的第184位含有一个高度保守的N - 糖基化位点，而该实体在MARC - 145细胞生长的生物制剂中含量较少。由于糖蛋白2参与感染性，这种额外的糖基化可能会增强病毒在猪肺泡巨噬细胞中的复制。
