細胞培養雞傳染性支氣管炎疫苗之研發

雞傳染性支氣管炎病毒(Avian infectious bronchitis virus；IBV)屬於冠狀病毒屬之具封套膜單股正鏈 RNA 病毒。由於不同血清型間的 IBV 缺乏交叉保護力，因此需要針對新的血清型 IBV 開發疫苗。IBV 可於雞胚胎中增殖。但目前以雞胚胎增殖病毒株有 SPF 雞胚胎取得不易、成本過高以及雞胚胎廢棄物處理之環保問題。因此本研究將建立培養 IBV 之合適細胞系以生產病毒，目前利用 Vero 細胞培養 IBV 經 30 代馴化其病毒量可達 106 TCID50 /mL，對照雞傳染性支氣管炎活毒疫苗之檢定標準，相當於 107.3 EID50 /mL，細胞可以觀察到明顯的融合、空泡化與脫落死亡的 CPE 現象，以 103 TCID50 /mL 至 106 TCID50 /mL 之病毒量製備成活毒疫苗免疫於雞隻，其 ELISA 測得之抗體力價於免疫後 2 至 3 週有明顯的上升，能夠穩定維持至少 8 週，以血清中和試驗測得之抗體力價最高可達 8 倍，其抗體可持續維持至免疫後第 10 週，綜合試驗結果，顯示具開發細胞培養雞傳染性支氣管炎活毒疫苗之潛力。

關鍵字

雞傳染性支氣管炎病毒；交叉保護力； Vero 細胞；活毒疫苗

並列摘要

Avian infectious bronchitis virus (IBV) belongs to coronavirus. It is an enveloped, single-stranded, positive-sense RNA virus. Because different serotypes of the virus don’t give cross-protection, it is necessary to develop a vaccine against the new serotype IBV. IBV can proliferate in chicken embryos. At present, however, it is not easy to obtain the embryo of the SPF chicken since the cost is too high. Waste treatment of chicken embryo is also problematic. Therefore, this study will establish a suitable cell line to produce IBV . For now, we have cultured and passaged IBV by using Vero cells and the current titers of IBV up to 106 TCID50 /mL after 30 generations of passage. Compared with the standard of avian infectious bronchitis live vaccine, it is equivalent to 107.3 EID50 /mL. The cells can observe the CPE phenomenon of obvious fusion, vacuolization, shedding and death. The IBV live vaccines were prepared with the virus amount of 103 TCID50 /mL to 106 TCID50 /mL to immunize chickens. The antibody titer measured by ELISA showed a significant increase from 2 to 3 weeks after immunization. It could be stably maintained for at least 8 weeks. The neutralization antibody titer could reach 8x dilutions, and the antibody could be maintained until the 10th week after immunization. The comprehensive test results show the potential to develop a cell-cultured infectious bronchitis vaccine.