结核分枝杆菌三价DNA疫苗在奶牛体内诱导的免疫应答

摘要

[目的]研究结核分枝杆菌Ag85B、MPB64和MPT83抗原DNA疫苗在奶牛体内诱导的免疫应答.[方法]以PJW4303为载体,构建上述3种抗原基因的三价DNA疫苗,免疫6月龄荷斯坦奶牛3次.ELISA法检测免疫奶牛的特异性抗体滴度.利用双抗夹心ELISA定量测定免疫奶牛各月IFN-γ浓度.[结果]免疫前奶牛体内特异性抗体为阴性,1免、2免后抗体效价上升较缓,3免后抗体效价上升快.MPT83特异性抗体上升最快,抗体效价1:3200持续6个月；Ag85B特异性抗体效价1:3200持续2个月；MPT64特异性抗体效价较低.免疫奶牛中MPT83、Ag85B、MPT64三种蛋白诱导产生IFN-γ在3免后6个月到达最高,浓度分别为(1 098.95±16.5.03)、(711.45士110.43)、(355.06±72.76) pg/mL,阴性对照组PBS刺激IFN -γ浓度为(114.5±27.46)pg/mL.阴性对照与三种抗原相比,差异均极显著(P＜0.01).[结论]多价核酸疫苗能同时诱导机体产生细胞免疫应答和体液免疫应答,可能有利于增强疫苗对抗结核病的抗性.%The purpose of this study was to evaluate the immune response induced by DNA vaccine based on Mycobacterium tuberculosis Ag85B, MPT83 and MPT64 antigen in cow. Six months old Holstein Cows were immunized with the eukaryotic expression vector PJW4303. ELISA was used to detect the anti - Ag85B, MPT83 and MPT64 antibody titere in sera of the vaccinated cow and the concentration of IFN - ywas determined quantitatively with double antibodies sandwich ELISA. Specific antibody titere were negative with the preimmunization, which was increased slowly after the first and second injection and increased rapidly after third injection. MPT83 induced autibody titers were 1:3200 and kept for six months; Ag85B induced autibody titere were 1:3200 and kept for two months; MPT64 induced autibody titers were low. Antigen - specific IFN - ylevel of MPT83, Ag85B, MPT64 and PBS were (1 098.95 ± 165.03) pg/mL and (711.45 ± 110.43) pg/mL and (355.06 ±72.76) pg/mL and(114.5 ± 27.46) pg/mL after the sixth month of the third injection. The negative control group (PBS) showed very significant difference ( P < 0.01) with the three antigen groups. In conclusion, the triplevalent DNA vaccines stimulated cell - mediated immune responses as well as humoral responses. Our data suggest that polyvalent DNA vaccines are able to enhance protective response against M. TB.