Infectious bronchitis (IB) is an economically important disease of poultry that also serve as model for the understanding of other coronaviruses associated diseases. IB is considered as a major challenge to the poultry industry worldwide as a result of its effect on egg production, weight gain as well as mortality. Different IBV genotypes continue to emerge, thus, the need for broad based vaccines to curb the disease. Based on bioinformatic data obtained in this study, sets of monovalent (either M41 or CR88) and bivalent DNA vaccines encoding the S1 glycoprotein from two different strains namely, M41 and CR88 were developed. The candidate vaccine was further encapsulated with a chitosan-saponin nanoparticle with the view to enhance its immunogenicity. Following in vitro characterization of the constructs, the vaccine candidates were tested in specific pathogen free (SPF) chickens. Analysis of humoral responses revealed a significant increase in anti-IBV antibody after immunization with the bivalent DNA plasmid (pBudCR88-S1/M41-S1). Likewise, cell mediated immune (CMI) response was significantly higher in vaccinated groups as compared to the unvaccinated chickens. Vaccinated chickens exhibited milder clinical signs as well as tracheal and kidney lesion scores following virus challenge as compared to the control groups. Additionally, encapsulation of the bivalent DNA vaccine with chitosan-saponin nanoparticles was found to improve protection against challenge with IBV strains M41 and CR88 as revealed by a significant reduction (p < 0.05) in oropharyngeal and cloacal virus sheddings following challenges with each of the two viruses. In contrast, monovalent IB-DNA vaccines were protective against homologous virus challenge. Moreover, nanoencasulation of the candidate vaccine was demostrated to abrogate the need for booster vaccination. In conclusion, this study demonstrates the immunogenic potentials of a bivalent IB-DNA vaccine and the use of chitosan-saponin nanoparticle to enhance its response. This development could serve as alternative strategy for the control of IB in poultry.

传染性支气管炎 (IB) 是一种经济上重要的家禽疾病，也是了解其他冠状病毒相关疾病的模型。由于 IB 对产蛋量、体重增加和死亡率的影响，IB 被认为是全球家禽业面临的主要挑战。不同的 IBV 基因型不断出现，因此需要基础广泛的疫苗来遏制该疾病。基于本研究中获得的生物信息学数据，开发了一组单价（M41 或 CR88）和二价 DNA 疫苗，这些疫苗编码来自两种不同菌株（即 M41 和 CR88）的 S1 糖蛋白。候选疫苗进一步用壳聚糖-皂苷纳米颗粒包裹，以增强其免疫原性。继体外为了表征构建体，候选疫苗在无特定病原体 (SPF) 的鸡中进行了测试。体液反应分析表明，在用二价 DNA 质粒 (pBudCR88-S1/M41-S1) 免疫后，抗 IBV 抗体显着增加。同样，与未接种疫苗的鸡相比，接种疫苗组的细胞介导免疫 (CMI) 反应明显更高。与对照组相比，接种疫苗的鸡在病毒攻击后表现出较轻的临床症状以及气管和肾脏损伤评分。此外，发现用壳聚糖-皂苷纳米颗粒包封二价 DNA 疫苗可提高对 IBV 毒株 M41 和 CR88 攻击的保护作用，显着降低 (p < 0. 05) 在对两种病毒中的每一种进行攻击后口咽和泄殖腔病毒脱落中。相比之下，单价 IB-DNA 疫苗对同源病毒攻击具有保护作用。此外，候选疫苗的纳米封装被证明可以消除加强疫苗接种的需要。总之，这项研究证明了二价 IB-DNA 疫苗的免疫原性潜力以及使用壳聚糖-皂苷纳米颗粒来增强其反应。这一发展可以作为控制家禽 IB 的替代策略。这项研究证明了二价 IB-DNA 疫苗的免疫原性潜力以及使用壳聚糖-皂苷纳米颗粒来增强其反应。这一发展可以作为控制家禽 IB 的替代策略。这项研究证明了二价 IB-DNA 疫苗的免疫原性潜力以及使用壳聚糖-皂苷纳米颗粒来增强其反应。这一发展可以作为控制家禽 IB 的替代策略。