The study was conducted to evaluate the immune response of pigs vaccinated intramuscularly (IM) or intradermally (ID) with porcine reproductive and respiratory syndrome virus 1 (PRRSV-1) modified live vaccine (MLV). The protective efficacy was evaluated upon challenge with highly pathogenic (HP)-PRRSV-2, either alone or in combination with PRRSV-1. Forty-two, castrated male, PRRSV-free pigs were randomly allocated into 7 groups of 6 pig each. IM/HPPRRSV2, IM/CoChallenge, ID/HPPRRSV2 and ID/CoChallenge groups were vaccinated IM or ID with PRRSV-1 MLV (UNISTRAIN® PRRS, Laboratorios Hipra S.A., Amer, Spain) in accordance to the manufacturer's directions. NV/HPPRRSV2 and NoVac/CoChallenge groups were nonvaccinated/challenged controls. NoVac/NoChallenge group was left as the control. Antibody response, IFN-γ-secreting cells (IFN-γ-SC) and IL-10 production were evaluated following vaccination. At 35 days post vaccination (DPV), all challenged groups were intranasally inoculated with HP-PRRSV-2, either alone or in combination with PRRSV-1. PRRSV viremia and lung lesion scores were evaluated following challenge. The results demonstrated that ID vaccinated pigs had significantly lower IL-10 levels and higher IFN-γ-SC than that of IM vaccinated pigs. Following challenge with HP-PRRSV-2 either alone or with PRRSV-1, PRRSV viremia and lung lesions, both macroscopically and microscopically, were significantly reduced in vaccinated pigs than that of nonvaccinated pigs, regardless to the route of vaccine administration. ID vaccinated pigs had significantly lower levels of PRRSV viremia and lung lesion scores than that of IM vaccinated pigs. The results of the study suggested that the administration of PRRSV-1 MLV, either IM or ID, provided partial protection against HP-PRRSV-2, either alone or when cochallenged with PRRSV-1, as demonstrated by the reduction in lung lesions and viremia. The ID route might represent an alternative to improve vaccine efficacy, as it resulted in lower IL-10 levels and higher IFN-γ-SC levels.

中文翻译：

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猪繁殖与呼吸综合征病毒1（PRRSV-1）修饰的活疫苗肌肉注射和皮内接种疫苗对高致病性PRRSV-2（HP-PRRSV-2）攻击的免疫应答和单独使用，或与PRRSV- 1。

进行该研究以评估用猪生殖和呼吸综合征病毒1（PRRSV-1）改良活疫苗（MLV）肌肉注射（IM）或皮内注射（ID）的猪的免疫反应。单独或与PRRSV-1联合使用高致病性（HP）-PRRSV-2进行攻击后，评估保护效果。将42只cast割的无PRRSV雄性猪随机分为7组，每组6头。IM / HPPRRSV2，IM / CoChallenge，ID / HPPRRSV2和ID / CoChallenge组按照PRRSV-1 MLV（UNISTRAIN®PRRS，Laboratorios Hipra SA，西班牙，阿米尔，西班牙）按照制造商的指示接种了IM或ID。NV / HPPRRSV2和NoVac / CoChallenge组为未接种疫苗/挑战对照组。NoVac / NoChallenge组留作对照。抗体反应 接种疫苗后评估分泌IFN-γ的细胞（IFN-γ-SC）和IL-10的产生。接种疫苗（DPV）后35天，所有感染组均单独或与PRRSV-1鼻内接种HP-PRRSV-2。挑战后评估PRRSV病毒血症和肺损伤评分。结果表明，与IM疫苗接种的猪相比，ID疫苗接种的猪IL-10水平明显降低，IFN-γ-SC更高。单独使用HP-PRRSV-2或PRRSV-1攻击后，无论疫苗接种途径如何，与未接种疫苗的猪相比，接种疫苗的猪在宏观和微观上均显着减少了PRRSV病毒血症和肺部病变。接种ID的猪比接种IM的猪PRRSV病毒血症和肺部病变得分低得多。研究结果表明，无论是单独使用还是与PRRSV-1联合使用，IM或ID的PRRSV-1 MLV均可单独提供抗HP-PRRSV-2的部分保护，如肺部病变和病毒血症的减少所证明。ID途径可能代表提高疫苗功效的替代方法，因为它导致较低的IL-10水平和较高的IFN-γ-SC水平。