HSV-1 VP22和hIL-18增强HBV DNA微球疫苗诱导的小鼠体液免疫应答

为了研究HSV-1VP22和hIL-18作为分子佐剂对HBVDNA微球疫苗诱导小鼠体液免疫应答的影响,HSV病毒经Vero细胞培养增殖后,提取病毒DNA,PCR扩增VP22编码基因。从人PBMC中提取总RNA,RT-PCR扩增hIL-18。VP22、hIL-18按不同需要插入pcDNA3.1-S,构建成3种质粒:pcDNA3.1-VP22-S、pcDNA3.1-S-IL-18、pcDNA3.1-VP22-S-IL-18。制备DNA壳聚糖微球疫苗,鼻腔免疫小鼠,同时裸质粒DNA肌注小鼠,ELISA检测小鼠血清IgG、粪便sIgA水平。结果,与pcDNA3.1-S相比,pcDNA3.1-VP22-S、pcDNA3.1-S-IL-18、pcDNA3.1-VP22-S-IL-18均能引起小鼠血清IgG、粪便sIgA水平升高。在鼻腔免疫实验中,pcDNA3.1-VP22-S、pcDNA3.1-S-IL-18、pcDNA3.1-VP22-S-IL-18免疫组的血清IgG水平均在第8周达到最高,并且与pcDNA3.1-S相比,抗体水平有差异(P<0.05)。研究结果表明,VP22和hIL-18能够增强乙肝DNA疫苗的体液免疫应答;制备的DNA微球疫苗经鼻腔免疫后,能够诱导黏膜免疫应答。

The humoral immune responses induced by the HBV DNA microsphere vaccine improved with HSB-1 VP22 and hIL-18

To determine whether HSV-1 VP22 and hIL-18 could be used as the molecular adjuvant for HBV DNA vaccine to improve the antibody responses produced, virus DNA extracted from HSV-1 propagated in Vero cells and the total RNA isolated from human PBMC were used as templates to amplify VP22 and hIL-18 respectively by PCR. Furthermore, genes of VP22 and hIL-18 were to be inserted into pcDNA3.1 to construct three different plasmids; i.e. pcDNA3.1-VP22-S, pcDNA3.1-S-IL-18, and pcDNA3.1-VP22-S-IL-18. Chitosan-pDNA microsphere was prepared and then was used to immunize mice through intranasal route, and simultaneously inoculated with naked DNA by intramuscular route. ELISA assay was used to detect the presence of serum IgG and fecal IgA of mice. The experimental result showed that in comparison with pcDNA3.1-S, all these three plasmids could induce an elevation of the serum IgG and fecal sIgA levels of mice. Especially in the group of mice with intranasal immunization, titers of serum IgG of mice immunized with pcDNA3.1-VP22-S, pcDNA3.1-S-IL-18 and pcDNA3.1-VP22-S-IL-18 reached the highest point at 8th week, and compared with pcDNA3.1-S, the difference was significant (P<0.05). These results demonstrated that VP22 and hIL-18 can improve the antibody responses induced by HBV DNA vaccine and the formulated microsphere vaccine can also induce the mucosal immune responses when immunized by intranasal route.