Fraunhofer Institute for Molecular Biology and Applied Ecology IME, Aachen, Germany.
Institute of Poultry Diseases, Faculty of Veterinary Medicine, Freie Universität Berlin, Berlin, Germany.
PLoS One. 2013 Dec 20;8(12):e83210. doi: 10.1371/journal.pone.0083210. eCollection 2013.
Infectious bursal disease virus (IBDV) causes economically important immunosuppressive disease in young chickens. The self-assembling capsid protein (VP2) from IBDV strain IR01 was expressed in Pichia pastoris resulting in the formation of homomeric, 23-nm infectious bursal disease subviral particles (IBD-SVPs) with a yield of 76 mg/l before and 38 mg/l after purification. Anti-IBDV antibodies were detected in chickens injected with purified IBD-SVPs or fed with either purified IBD-SVPs or inactivated P. pastoris cells containing IBD-VP2 (cell-encapsulated). Challenge studies using the heterologous classical IBDV strain (MB3) showed that intramuscular vaccination with 20 µg purified IBD-SVPs conferred full protection, achieved complete virus clearance and prevented bursal damage and atrophy, compared with only 40% protection, 0-10% virus clearance accompanied by severe atrophy and substantial bursal damage in mock-vaccinated and challenge controls. The commercial IBDV vaccine also conferred full protection and achieved complete virus clearance, albeit with partial bursal atrophy. Oral administration of 500 µg purified IBD-SVPs with and without adjuvant conferred 100% protection but achieved only 60% virus clearance with adjuvant and none without it. Moderate bursal damage was observed in both cases but the inclusion of adjuvant resulted in bursal atrophy similar to that observed with live-attenuated vaccine and parenteral administration of 20 µg purified IBD-SVPs. The oral administration of 250 mg P. pastoris cells containing IBD-VP2 resulted in 100% protection with adjuvant and 60% without, accompanied by moderate bursal damage and atrophy in both groups, whereas 25 mg P. pastoris cells containing IBD-VP2 resulted in 90-100% protection with moderate bursal lesions and severe atrophy. Finally, the oral delivery of 50 µg purified IBD-SVPs achieved 40-60% protection with severe bursal lesions and atrophy. Both oral and parenteral administration of yeast-derived IBD-VP2 can therefore induce a specific and protective immune response against IBDV without affecting the growth rate of chickens.
传染性腔上囊病病毒 (IBDV) 可导致雏鸡发生具有重要经济意义的免疫抑制性疾病。IBDV 株 IR01 的自组装衣壳蛋白 (VP2) 在巴斯德毕赤酵母中表达，导致形成同源 23nm 的传染性腔上囊病亚病毒颗粒 (IBD-SVPs)，在纯化前的产量为 76mg/L，在纯化后的产量为 38mg/L。用纯化的 IBD-SVPs 注射的鸡体内检测到抗 IBDV 抗体，或用纯化的 IBD-SVPs 或含有 IBD-VP2 的巴斯德毕赤酵母细胞 (细胞包被) 喂养的鸡体内也检测到了抗 IBDV 抗体。使用异源经典 IBDV 株 (MB3) 进行的攻毒研究表明，与仅 40%的保护率、0-10%的病毒清除率、伴有严重萎缩和实质性腔上囊损伤的对照相比，肌肉内接种 20µg 纯化的 IBD-SVPs 可完全保护、实现完全病毒清除，并预防腔上囊损伤和萎缩。商业 IBD 疫苗也可提供完全保护并实现完全病毒清除，尽管存在腔上囊萎缩。口服 500µg 纯化的 IBD-SVPs 并添加佐剂可提供 100%的保护率，但添加佐剂的清除率为 60%，而不添加佐剂的清除率为 0%。在这两种情况下均观察到中等程度的腔上囊损伤，但添加佐剂会导致与活疫苗相似的腔上囊萎缩，以及与肌肉内注射 20µg 纯化的 IBD-SVPs 相关的腔上囊萎缩。口服 250mg 含有 IBD-VP2 的巴斯德毕赤酵母细胞在添加佐剂时可提供 100%的保护率，而不添加佐剂时为 60%，两组均伴有中度腔上囊损伤和萎缩，而 25mg 含有 IBD-VP2 的巴斯德毕赤酵母细胞在添加佐剂时可提供 90-100%的保护率，伴有中度腔上囊损伤和严重萎缩。最后，口服 50µg 纯化的 IBD-SVPs 可提供 40-60%的保护率，伴有严重的腔上囊损伤和萎缩。酵母来源的 IBD-VP2 的口服和肌肉内给药均可诱导针对 IBDV 的特异性和保护性免疫应答，而不会影响鸡的生长速度。
