Department of Veterinary Microbiology, Faculty of Veterinary Science, Chulalongkorn University, Bangkok 10330, Thailand.
Department of Pharmaceutics and Industrial Pharmacy, Faculty of Pharmaceutical Sciences, Chulalongkorn University, Bangkok 10330, Thailand.
Vet Microbiol. 2020 May;244:108655. doi: 10.1016/j.vetmic.2020.108655. Epub 2020 Mar 27.
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.
本研究旨在评估经肌肉（IM）或皮内（ID）接种猪繁殖与呼吸综合征病毒 1（PRRSV-1）活疫苗（MLV）的猪的免疫反应。通过单独或与 PRRSV-1 联合挑战高致病性（HP）-PRRSV-2 来评估保护效力。42 头去势雄性 PRRSV 阴性猪被随机分为 7 组，每组 6 头。IM/HPPRRSV2、IM/CoChallenge、ID/HPPRRSV2 和 ID/CoChallenge 组按照制造商的说明，分别通过肌肉或皮内接种 PRRSV-1 MLV（UNISTRAIN® PRRS，Laboratorios Hipra S.A.，Amer，西班牙）进行免疫。NV/HPPRRSV2 和 NoVac/CoChallenge 组为未接种/对照攻毒组。NoVac/NoChallenge 组作为对照。接种后评估抗体反应、IFN-γ 分泌细胞（IFN-γ-SC）和 IL-10 产生。在接种后 35 天（DPV），所有攻毒组均通过鼻腔接种 HP-PRRSV-2，单独或与 PRRSV-1 联合接种。攻毒后评估 PRRSV 血症和肺损伤评分。结果表明，与肌肉接种相比，皮内接种的猪的 IL-10 水平显著降低，IFN-γ-SC 水平显著升高。单独或与 PRRSV-1 联合接种 HP-PRRSV-2 后，无论疫苗接种途径如何，接种猪的 PRRSV 血症和肺损伤，无论是宏观还是微观，均显著低于未接种猪。皮内接种的猪的 PRRSV 血症和肺损伤评分均显著低于肌肉接种的猪。研究结果表明，肌肉或皮内接种 PRRSV-1 MLV 均可提供对 HP-PRRSV-2 的部分保护，无论是单独接种还是与 PRRSV-1 联合接种，均可通过降低肺损伤和病毒血症来证明。皮内接种可能是提高疫苗效力的一种替代方法，因为它导致更低的 IL-10 水平和更高的 IFN-γ-SC 水平。
