傳染性華氏囊病疫苗之研發

傳染性華氏囊炎(Infectious bursal disease；IBD)，是由傳染性華氏囊病毒(Infectious bursal disease virus；IBDV)所引起，主要會感染3～6週齡的雞隻，造成B淋巴芽細胞壞死及嚴重的免疫抑制，且具高度傳染性。IBDV屬於雙核糖核酸病毒科(Birnaviridae)禽病毒屬(Avibirnavirus)。IBDV主要的外殼蛋白為VP2及VP3，其中VP2蛋白上的高度變異區具有誘發中和抗體的抗原決定位。原先出現的IBDV可以被減毒疫苗所控制，隨著病毒變異出現了超強毒型IBDV(very virulent IBDV；vvIBDV)，vvIBDV的VP2胺基酸點位發生改變，使其具有高病原性且會引起急性臨床症狀，導致死亡率上升，台灣也在1993年發現了高病原性的本土強毒株。本次研究選用台灣本土分離之vvIBDV263/TW02，其VP2基因為1464bp。以PCR擴增VP2全長基因，再轉殖到桿狀病毒表現系統製作次單位蛋白，並結合細胞培養之減毒疫苗，將兩者混合以活毒稀釋用佐劑乳化後，對SPF雞隻進行免疫，接著透過V263/TW02直接攻毒測試疫苗效力。結果顯示自製疫苗可提供有效保護，淋巴濾泡並未有嚴重受損，華氏囊也未出現萎縮之情形。

關鍵字

傳染性華氏囊病；次單位蛋白；疫苗；桿狀病毒表現系統

並列摘要

Infectious bursal disease (IBD) is caused by infectious bursal disease virus (IBDV). It infects chickens aged 3 to 6 weeks, then causing necrosis of B-lymphoblast and serious immunosuppression and is highly contagious. IBDV belongs to the Avibirnavirus of the Birnaviridae family. The capsid proteins of IBDV are VP2 and VP3. VP2 has epitopes in highly variable regions, which can induce the production of neutralizing antibodies. The IBDV that originally appeared can be controlled by attenuated vaccines. With the mutation of the virus, very virulent IBDV (very virulent IBDV; vvIBDV) appears, and the VP2 amino acid site of vvIBDV has changed, making it highly pathogenic and causing acute clinical symptoms. It increases mortality. Taiwan also discovered a highly pathogenic indigenous virulent strain in 1993. In this study, vvIBDV263/TW02 isolated from Taiwan was selected, and its VP2 gene is 1464bp. Amplify the full-length VP2 gene by PCR, and then transfer it to the baculovirus expression system to produce subunit protein, combining with the cell culture attenuated vaccine. The two were mixed and emulsified with a live virus dilution adjuvant, and immunized SPF chickens, then directly challenged with V263/TW02 to test the efficacy of the vaccine. The results show that the self-prepared vaccine can provide effective protection. The lymphoid follicles were not severely damaged, and the bursal did not shrink.