Serum concentration of acute phase proteins and cytokines in vaccinated pigs challenged with foot-and-mouth disease virus serotype O

ABSTRACT The present study aimed to investigate the kinetics of acute phase proteins and cytokines in the serum of immunized or naive pigs following infection with a field isolate of foot-and-mouth disease (FMD) virus. Five-month-old SPF pigs were intramuscularly immunized with or without the 146S antigen (7.5 μg per head) purified from FMD virus (O/Andong/SKR/2010) and were subsequently challenged 30 days post-vaccination (dpv) with FMD virus on each footpad. Serum samples were obtained at 28 dpv and on days 1, 3, and 5 post-infection (dpi). At 28 dpv, the serum concentrations of C-reactive protein and tumor necrosis factor alpha (TNF-α) were higher in the immunized pigs compared with the non-immunized control pigs. Upon challenge, the levels of all measured acute phase proteins (i.e., C-reactive protein, major acute phase protein, S-amyloid A, and haptoglobin) plateaued at 1 dpi in the immunized pigs whereas they gradually increased up to 5 dpi in the non-immunized control pigs. Levels of serum TNF-α remained higher in the immunized challenged pigs compared with the non-immunized challenged pigs. The serum concentration of interleukin (IL)-6 in the immunized challenged pigs was undetectable at all time points, but moderately increased upon challenge in the non-immunized challenged pigs. IL-1β was not detected in any of the pigs at any of the observed time points. Collectively, these findings show that the immunized pigs exhibit a rapid serum acute phase protein response following subsequent challenge with the field FMD virus compared with the non-immunized pigs.

摘要 本研究旨在探究接种疫苗或未免疫仔猪在感染口蹄疫（FMD）病毒野外分离株后，其血清中急性期蛋白与细胞因子的动态变化规律。选取5月龄无特定病原体（SPF）仔猪，分别肌内注射从口蹄疫病毒O/Andong/SKR/2010株中纯化的146S抗原（每头7.5μg）或不注射抗原，随后于疫苗接种后30天（dpv），在每只足垫接种口蹄疫病毒进行攻毒。分别于疫苗接种后28天以及攻毒后1、3、5天（dpi）采集血清样本。疫苗接种后28天，免疫组仔猪血清中的C反应蛋白（CRP）与肿瘤坏死因子α（TNF-α）浓度均高于未免疫对照组仔猪。攻毒后，免疫组仔猪所有检测的急性期蛋白（即C反应蛋白、主要急性期蛋白、血清淀粉样蛋白A与结合珠蛋白）水平均在攻毒后1天达到平台期，而未免疫对照组仔猪的上述蛋白水平则持续升高至攻毒后5天。免疫攻毒组仔猪的血清TNF-α水平仍高于未免疫攻毒组仔猪。免疫攻毒组仔猪的血清白细胞介素6（IL-6）浓度在所有采样时间点均未检出，而未免疫攻毒组仔猪的IL-6水平在攻毒后出现轻度升高。所有采样时间点的所有仔猪血清中均未检出IL-1β。综上，本研究结果表明，与未免疫仔猪相比，免疫组仔猪在感染口蹄疫病毒野外分离株后，血清急性期蛋白应答更为迅速。