含粘膜佐剂的鸡新城疫疫苗诱导雏鸡非特异性免疫应答的研究

ADDITION OF HEAT-LABILE ENTEROTOXIN AS ADJUVANT TO NEWCASTLE DISEASE VACCINE ENHANCES NON-SPECIFIC IMMUNE RESPONSES IN CHICKENS

为研究分析重组大肠杆菌不耐热肠毒素(labile enterotoxin,LT)作为粘膜佐剂,配伍鸡新城疫疫苗的冻干样品对免疫鸡非特异性免疫应答的影响,在前期已经构建的LTR72/G192基础上,选择2、4μg LTRG蛋白作为每羽份疫苗添加量,及降低新城疫病毒(Newcastle disease virus,NDV)50%抗原量等配伍条件。按照生产条件制备冻干疫苗,进行雏鸡免疫试验,免疫后24、48、72 h采集脾脏、胸腺淋巴结,检测几种非特异性细胞因子表达水平。结果表明:IL-6、INF-γ水平在各疫苗免疫后24h即升高,48 h达最高值;添加2、4μg LTRG蛋白的NDV疫苗组IFN-β、TNF-α水平在48 h左右显著升高,其中含4μg LTRG疫苗组与其他组差异具有极显著统计学意义(P<0.01);IL-6、IFN-γ转录水平有所增强,但各组间差异不具有显著统计学意义(P>0.05),72 h左右几种细胞因子水平均迅速下降,与NDV疫苗接种组相近。由此可见,LTRG能辅助抗原诱导免疫雏鸡的非特异性免疫应答,有利于对感染病毒的清除。

In the present study, heat-labile enterotoxin （LT） was used as adjuvants for Newcastle disease virus （NDV） vaccine to investigate if non-specific immune responses were enhanced in vaccinated chickens. The formulation procedure was to add 2μg or 4μg LTRG to one dose of NDV vaccine or 4μg LTRG to half dose of vaccine followed by freeze-drying cycles. The aduvanted NDV vaccines were orally administered to chickens. At 24, 48 h and 72 h post vaccination, spleens, thymuses and lymph nodes were collected and levels of IL-6, INF-γ, IFN-β and TNF-ct were detected in Real-time PCR. The results showed that IL-6 and INF-y of all vaccinated chickens started to rise at 24 h and peaked at 48 h post vaccination while IFN-β and TNF-α did not significantly increase till 48 h post vaccination.In addition, chickens vaccinated with NDV vaccine containing 4 μg LTRG developed significantly （P〈0.01） higher IL-6 and INF-γ responses than NDV alone controls. The transcription levels of IL-6 and INF-γ increased but difference among groups was not significant （P〉0.05）. In conclusion, addition of LTRG to NDV vaccine enhanced non-specific immune responses in vaccinated chickens.