重组SEA增强H5亚型禽流感灭活疫苗对肉鸡的免疫效果研究

为评价重组葡萄球菌肠毒素A(rSEA)对H5亚型禽流感病毒(AIV)灭活疫苗免疫效果的影响,本研究以原核表达的rSEA为免疫增强剂,制备成含有rSEA高(167 μg/0.5 mL)、低(16.7 μg/0.5 mL)两种剂量的AIV油乳剂灭活苗,分别免疫7d龄肉鸡,通过检测免疫鸡AIV HI抗体滴度及外周血CD4+/CD8+值评价其免疫效果.HI 抗体检测结果显示,免疫后2周高剂量组HI抗体平均滴度为5.6 log2,低剂量组为4.2 log2,而无rSEA疫苗对照组为2.9 log2(p＜0.01)；同时在免疫后前4周,rSEA免疫组的HI抗体平均滴度及峰值与对照组相比均差异显著(p＜0.05).T淋巴细胞亚群检测结果显示,肉鸡免疫高剂量rSEA的灭活苗后,其外周血CD4+百分含量及CD4+/CD8+值均显著高于对照组(p＜0.05).上述结果表明,rSEA作为AIV灭活苗免疫增强剂,能够快速诱导较高的HI抗体滴度,同时也可增强细胞免疫反应,有效缩短免疫空白期,使肉鸡短时间内产生较强的免疫应答反应.

Efficacy of rSEA adjuvanted H5 subtype avian influenza oil-emulsion inactivated vaccine in broilers

To assess enhancement of recombinant staphylococcal enterotoxin A(rSEA) to inactivated H5 subtype avian influenza viruses(AIV) vaccine,7-day-old broilers were inoculated intramuscularly with oil-emulsion AIV vaccine adjuvanted with either high(167 μg/0.5 mL) or low(16.7 μg/0.5 mL) of rSEA.Sera and peripheral blood mononuclear cells(PBMC) were collected for detection of HI antibody titers and ratio of CD4+ and CD8+ T lymphocyte,respectively.The results showed that the average HI antibody titers reached 5.6 log2 in immunized group with high rSEA dose vaccine and 4.2log2 with low rSEA dose vaccine at 2 weeks post-vaccination,which was more significant(p<0.01) than that of 2.9log2 in control group immunized with the vaccine without rSEA.In addition,the average HI antibody titers and peaks in both rSEA adjuvanted groups were significant difference compared with control group during the initial period of 4-week(p<0.05).The T lymphocyte subpopulation assay showed that the CD4+ and CD4+/CD8+ ratio in high rSEA dose group were higher than control group(p<0.05).These results indicated that rSEA as an immune-enhancer was able to triggered early-onset both humoral and cell-mediated immune response compared to the conventional vaccine in broilers.