Rasool Muhammad Hidayat, Hussain Iftikhar
Department of Veterinary Microbiology, Faculty of Veterinary Sciences, University of Agriculture, Faisalabad 38040, Pakistan.
Vaccine. 2006 Apr 5;24(15):2810-4. doi: 10.1016/j.vaccine.2006.01.044. Epub 2006 Feb 7.
The present work was carried out to develop an effective vaccine to control infectious bursal disease (IBD). The very virulent infectious bursal disease virus (vvIBDV) was adapted to grow in Vero-cell line after three serial passages. The virus was then attenuated by further serial passages and pathogenicity of different passages was determined in broiler chicks free from antibodies against IBDV. The ninth passage virus was completely attenuated, as it was non-pathogenic to chicks. The birds inoculated with ninth passage virus had bursa to body weight ratio comparable to un-inoculated control and zero mean lesion score. This ninth passage virus was evaluated as live attenuated Vero-cell adapted vaccine. A commercial live cell culture origin vaccine (IBD-VAC, Korea) was used for comparison. Experimental trials were conducted in 3-week-old broiler chicks. Clinical signs, gross and histopathological lesions and bursa to body weight ratio were all comparable to un-vaccinated control group in case of live attenuated Vero-cell vaccine (group A). High virus-neutralizing antibody titres were also found at 7, 14, and 21 days post-vaccination in group A. On challenge, 100% protection was achieved in group A and 65% in case of commercial vaccine (group B) in terms of bursal lesions. All the birds in control group showed sever bursal lesions post-challenge. The study indicated newly developed infectious bursal disease vaccine was found to be safe and immunogenic.
开展本研究是为了研发一种有效的疫苗来控制传染性法氏囊病（IBD）。超强毒传染性法氏囊病病毒（vvIBDV）经过三次连续传代后适应在Vero细胞系中生长。然后通过进一步连续传代使病毒减毒，并在无IBDV抗体的肉鸡雏鸡中测定不同传代病毒的致病性。第九代传代病毒完全减毒，因为它对雏鸡无致病性。接种第九代传代病毒的鸡的法氏囊与体重之比与未接种的对照组相当，平均病变评分为零。该第九代传代病毒被评估为Vero细胞适应的减毒活疫苗。使用一种市售的活细胞培养源疫苗（IBD - VAC，韩国）进行比较。在3周龄的肉鸡雏鸡中进行了实验试验。在使用Vero细胞减毒活疫苗的情况下（A组），临床症状、大体和组织病理学病变以及法氏囊与体重之比均与未接种疫苗的对照组相当。在A组接种疫苗后第7、14和21天也发现了高病毒中和抗体滴度。在攻毒时，就法氏囊病变而言，A组实现了100%的保护，市售疫苗组（B组）为65%。对照组所有鸡在攻毒后均出现严重的法氏囊病变。该研究表明新研发的传染性法氏囊病疫苗安全且具有免疫原性。
