牛病毒性腹泻病毒E0基因重组嗜酸乳杆菌pMG36e-E0-LA-5对犊牛的免疫保护作用

Protective efficacy of recombinant Lactobacillus acidophilus pMG36e-E0-LA-5 against bovine viral diarrhea virus in calves

将构建的牛病毒性腹泻病毒(BVDV)E0基因重组嗜酸乳杆菌pMG36e-E0-LA-5免疫犊牛,观察其对犊牛抗BVDV感染的免疫保护效果。选取1月龄犊牛,随机挑选20头分成4组,每组5只。1~3组为免疫组,分别口服接种1,5,10 mL重组嗜酸乳杆菌pMG36e-E0-LA-5(1010 CFU/mL),共免疫3次,每次连续免疫3 d,每次免疫间隔1周;第4组为空白对照组。分别于免疫后0,10,20,30 d检测血清IgG和粪便sIgA的水平和白细胞介素-12(IL-12)表达水平。三免后7 d用BVDV攻毒,5 mL/只(105.5/mL TCID50),观察免疫犊牛对BVDV感染的免疫保护效果。结果显示,pMG36e-E0-LA-5免疫犊牛体内血清IgG抗体和粪便sIgA抗体含量、血清IL-12表达水平显著高于对照组(P<0.05或P<0.01),且对BVDV感染的保护率明显高于对照组。结果表明,pMG36e-E0-LA-5免疫犊牛,可诱生血清IgG和粪便sIgA类抗体,提高机体IL-12表达水平,有效抵抗BVDV的感染。本试验为研制用于预防BVDV感染的嗜酸乳杆菌活载体疫苗提供依据。

This research was conducted to test the protective efficacy of the recombinant Lactobacillus acidophilus(L.acidophilus)pMG36 e-E0-LA-5 against bovine viral diarrhea virus(BVDV).A total of 20 one-month-old calves were randomly divided into three treatment groups and a control group.The calves in treatment groups were immunized orally with the recombinant L.acidophilus pMG36 e-E0-LA-5(1010 CFU/mL)with three dosage groups of 1 mL,5 mL and 10 mL/calf respectively for 3 days,and a booster vaccination was given at the same dosage a week later for2 times.The serum IgG antibody and fecal sIgA antibody responses and expression levels of interleukin-12(IL-12)were detected respectively.On the 7 th day after the last-immunization,the calves were inoculated with BVDV(105.5/mL TCID50)at a dose of 5 mL/calf to evaluate the protective efficiency of the recombinant L.acidophilus pMG36 e-E0-LA-5.The results showed that the IgG and sIgA antibodies responses and IL-12 expression levels in the vaccinated calves with recombinant L.acidophilus pMG36 e-E0-LA-5 were significantly higher than those in the control calves(P<0.05 or P<0.01).The protective rate in immunized calves against BVDV increasedsignificantly,and a 90%protection rate in virulent challenge was observed.These results indicated that the recombinant L.acidophilus pMG36 e-E0-LA-5 strain could effectively improve the immune response in calves and might provide protection against BVDV.Thus,the recombinant L.acidophilus pMG36 e-E0-LA-5 strain can be an effective strategy for the immunoprophylaxis of BVDV.