Division of Pharmaceutical Sciences, Department of Pharmaceutical Care, Faculty of Pharmaceutical Sciences, University of Phayao, Phayao, 56000, Thailand.
Swine Viral Evolution and Vaccine Development Research Unit, Department of Veterinary Microbiology, Faculty of Veterinary Science, Chulalongkorn University, Bangkok, 10330, Thailand.
Sci Rep. 2022 Mar 8;12(1):3725. doi: 10.1038/s41598-022-07680-9.
This study was conducted to evaluate the induction of systemic and mucosal immune responses and protective efficacy following the intranasal administration of inactivated porcine reproductive and respiratory syndrome virus (PRRSV) loaded in polylactic acid (PLA) nanoparticles coupled with heat-labile enterotoxin subunit B (LTB) and dimethyldioctadecylammonium bromide (DDA). Here, 42- to 3-week-old PRRSV-free pigs were randomly allocated into 7 groups of 6 pigs each. Two groups represented the negative (nonvaccinated pigs/nonchallenged pigs, NoVacNoChal) and challenge (nonvaccinated/challenged, NoVacChal) controls. The pigs in the other 5 groups, namely, PLA nanoparticles/challenged (blank NPs), LTB-DDA coupled with PLA nanoparticles/challenged (adjuvant-blank NPs), PLA nanoparticles-encapsulating inactivated PRRSV/challenged (KNPs), LTB-DDA coupled with PLA nanoparticles loaded with inactivated PRRSV/challenged pigs (adjuvant-KNPs) and inactivated PRRSV/challenged pigs (inactivated PRRSV), were intranasally vaccinated with previously described vaccines at 0, 7 and 14 days post-vaccination (DPV). Serum and nasal swab samples were collected weekly and assayed by ELISA to detect the presence of IgG and IgA, respectively. Viral neutralizing titer (VNT) in sera, IFN-γ-producing cells and IL-10 secretion in stimulated peripheral blood mononuclear cells (PBMCs) were also measured. The pigs were intranasally challenged with PRRSV-2 at 28 DPV and necropsied at 35 DPV, and then macro- and microscopic lung lesions were evaluated. The results demonstrated that following vaccination, adjuvant-KNP-vaccinated pigs had significantly higher levels of IFN-γ-producing cells, VNT and IgG in sera, and IgA in nasal swab samples and significantly lower IL-10 levels than the other vaccinated groups. Following challenge, the adjuvant-KNP-vaccinated pigs had significantly lower PRRSV RNA and macro- and microscopic lung lesions than the other vaccinated groups. In conclusion, the results of the study demonstrated that adjuvant-KNPs are effective in eliciting immune responses against PRRSV and protecting against PRRSV infections over KNPs and inactivated PRRSV and can be used as an adjuvant for intranasal PRRSV vaccines.
这项研究旨在评估经鼻给予聚乳酸（PLA）纳米粒负载的灭活猪繁殖与呼吸综合征病毒（PRRSV）并偶联不耐热肠毒素亚单位 B（LTB）和二甲基双十八烷基溴化铵（DDA）后诱导全身和黏膜免疫应答及保护效力。在这里，将 42 至 3 周龄的 PRRSV 阴性猪随机分配到 7 组，每组 6 头。两组为阴性（未接种/未攻毒，NoVacNoChal）和攻毒（未接种/攻毒，NoVacChal）对照组。其余 5 组为 PLA 纳米粒/攻毒（空白 NPs）、LTB-DDA 偶联 PLA 纳米粒/攻毒（佐剂-空白 NPs）、PLA 纳米粒包封的灭活 PRRSV/攻毒（KNPs）、LTB-DDA 偶联负载灭活 PRRSV 的 PLA 纳米粒/攻毒（佐剂-KNPs）和灭活 PRRSV/攻毒（灭活 PRRSV）。猪在免疫接种后 0、7 和 14 天（DPV）经鼻接种上述疫苗。每周采集血清和鼻腔拭子样本，分别通过 ELISA 检测 IgG 和 IgA。还测量血清中的病毒中和滴度（VNT）、刺激外周血单核细胞（PBMC）中 IFN-γ产生细胞和 IL-10 分泌。猪在 DPV 后 28 天经鼻攻毒 PRRSV-2，在 DPV 后 35 天剖检，然后评估肺的宏观和微观病变。结果表明，接种后，佐剂-KNP 组猪 IFN-γ产生细胞、血清 VNT 和 IgG 以及鼻腔拭子 IgA 水平显著高于其他接种组，IL-10 水平显著低于其他接种组。攻毒后，佐剂-KNP 组猪的 PRRSV RNA 水平以及肺的宏观和微观病变显著低于其他接种组。总之，该研究结果表明，佐剂-KNPs 可有效诱导针对 PRRSV 的免疫应答，并可保护猪免受 PRRSV 感染，其效果优于 KNPs 和灭活 PRRSV，可作为 PRRSV 鼻内疫苗的佐剂。
