Li X, Galliher-Beckley A, Pappan L, Trible B, Kerrigan M, Beck A, Hesse R, Blecha F, Nietfeld J C, Rowland R R, Shi J
Department of Anatomy and Physiology, 228 Coles Hall, College of Veterinary Medicine, Kansas State University, 1600 Denison Ave, Manhattan, KS 66506, USA.
Department of Anatomy and Physiology, 228 Coles Hall, College of Veterinary Medicine, Kansas State University, 1600 Denison Ave, Manhattan, KS 66506, USA ; Intrexon Corporation, 108 TW Alexander Drive, Durham, NC 27709, USA.
Biomed Res Int. 2014;2014:416727. doi: 10.1155/2014/416727. Epub 2014 Feb 26.
Porcine reproductive and respiratory syndrome (PRRS) is a high-consequence animal disease with current vaccines providing limited protection from infection due to the high degree of genetic variation of field PRRS virus. Therefore, understanding host immune responses elicited by different PRRSV strains will facilitate the development of more effective vaccines. Using IngelVac modified live PRRSV vaccine (MLV), its parental strain VR-2332, and the heterologous KS-06-72109 strain (a Kansas isolate of PRRSV), we compared immune responses induced by vaccination and/or PRRSV infection. Our results showed that MLV can provide complete protection from homologous virus (VR-2332) and partial protection from heterologous (KS-06) challenge. The protection was associated with the levels of PRRSV neutralizing antibodies at the time of challenge, with vaccinated pigs having higher titers to VR-2332 compared to KS-06 strain. Challenge strain did not alter the cytokine expression profiles in the serum of vaccinated pigs or subpopulations of T cells. However, higher frequencies of IFN-γ-secreting PBMCs were generated from pigs challenged with heterologous PRRSV in a recall response when PBMCs were re-stimulated with PRRSV. Thus, this study indicates that serum neutralizing antibody titers are associated with PRRSV vaccination-induced protection against homologous and heterologous challenge.
猪繁殖与呼吸综合征（PRRS）是一种具有严重后果的动物疾病，由于田间PRRS病毒的高度遗传变异，目前的疫苗对感染的保护作用有限。因此，了解不同PRRSV毒株引发的宿主免疫反应将有助于开发更有效的疫苗。我们使用英特威改良活PRRSV疫苗（MLV）、其亲本毒株VR-2332以及异源KS-06-72109毒株（PRRSV的堪萨斯分离株），比较了疫苗接种和/或PRRSV感染诱导的免疫反应。我们的结果表明，MLV可以提供针对同源病毒（VR-2332）的完全保护以及针对异源（KS-06）攻击的部分保护。这种保护与攻击时PRRSV中和抗体的水平相关，与KS-06毒株相比，接种疫苗的猪对VR-2332具有更高的滴度。攻击毒株并未改变接种疫苗猪血清中的细胞因子表达谱或T细胞亚群。然而，当用PRRSV重新刺激外周血单核细胞（PBMC）时，在回忆反应中，用异源PRRSV攻击的猪产生了更高频率的分泌IFN-γ的PBMC。因此，本研究表明血清中和抗体滴度与PRRSV疫苗接种诱导的针对同源和异源攻击的保护作用相关。
