面筋蛋白外啡肽B5对传染性支气管炎灭活疫苗免疫效果的影响

Gluten Exorphin B5Enhances Immunogenicity and Protective Efficacy of Infectious Bronchitis Virus Vaccine in Broilers

麦谷蛋白源外啡肽B5来源于麦谷蛋白酶解产物,具有阿片样活性。作者通过进一步优化化学合成工艺制备外啡肽B5,并将其添加到传染性支气管炎病毒（IBV）H120株灭活疫苗中,免疫后21d（35日龄）采用IBV M41株病毒液进行点眼、滴鼻攻毒。通过测定免疫仔鸡的生产性能、淋巴细胞增殖水平、血清抗体水平、临床症状及组织病理学变化等指标,评价外啡肽B5的应用效果。结果显示,经过化学合成工艺优化后获得了高纯度的外啡肽B5（HPLC浓度大于98%）,7～35日龄肉鸡的平均体增重试验组比对照组显著提高13.8%,料肉比试验组比对照组显著降低15.1%;同时一定浓度的外啡肽B5能够诱导肉仔鸡产生较强的淋巴细胞增殖反应（P〈0.01）,免疫鸡群抗体水平显著高于对照组,在IBV M41株攻毒试验中,试验组可以显著减轻病毒感染肉仔鸡临床症状,肺和肾无组织病理学变化,免疫保护率达到96.7%。外啡肽B5可望开发成一种新型动物功能性饲料添加剂或动物疫苗佐剂。

Gluten exorphin B5（GE-B5）was a food-derived opioid peptide identified in vitroin enzymatic digests of wheat gluten,and it was a good candidate of functional feed additives and adjuvant for vaccine development because of its immune function.In this study,we chemically synthesized GE-B5,and then added it to vaccine against infectious bronchitis virus（IBV）H120strain to immunize chickens for evaluating their growth performance,immunogenicity and protective efficacy.On 0,14,and 21 dpi,the changes in proliferation of peripheral blood mononuclear cells（PBMC）and serum antibody titer were evaluated respectively by MTT method and hemagglutination inhibition assay.The results showed that administration of GE-B5 significantly raised anti-IB antibody titer in the chicken serum and also markedly promoted PBMCs proliferation.Following challenge with IBV Mass 41 strain,chickens inoculated with GE-B5 showed fewer and less severe clinical signs,lower death rate,lower mortality and showed higher protection,as compared to those of the control groups.The result of pathological tissue section showed that the lung and kidney became shorter pathological phenomenon than the control group.This study confirmed that in addition to its immunoregulatory activity and immunopromoting effects,GE-B5 can also promote weight gain.These data have important implications for functional feed additives and novel adju-vants designed for future vaccines.