登革病毒1、2型单、双价病毒样颗粒的免疫原性研究

Immunogenicity research of monovalent and bivalent dengue 1 and dengue 2 virus-like particles

目的初步研究登革病毒1、2型单、双价病毒样颗粒(VLP)的免疫原性。方法表达纯化各型VLP,用纯化好的VLP免疫BALB/c小鼠,将BALB/c小鼠随机分PBS组、灭活DENV1、灭活DENV2、纯化VLP1、纯化VLP2、纯化VLP1+2组,以灭活病毒为阳性对照,PBS为阴性对照。ELISA法检测小鼠血清抗VLP抗体效价以及血清IFN-γ、TNF-α细胞因子水平,流式细胞术检测小鼠脾细胞CD4+细胞和CD8+细胞数。结果登革病毒1、2型单、双价VLP均能刺激免疫小鼠产生一定程度的抗血清效价,VLP1的抗体水平较VLP2的低,双价VLP组针对DENV2抗原的抗体水平上升明显,是单价VLP2的2～3倍;攻毒后,灭活DENV1和VLP2可以产生高水平的IFN-γ,分别为60和35pg/ml,双价VLP组的较低;VLP2组的TNF-α一直保持较高水平,双价VLP组中攻DENV2组的TNF-α水平较DENV1组高;三次免疫后,各实验组较之PBS组CD4+细胞的比例都有下降,而CD8+细胞变化不大,除灭活DENV1组有增加,其余各组都有减少。结论无论单、双价VLP均能刺激小鼠产生一定程度的体液免疫和细胞免疫反应,联合免疫有一定程度的协同性。

Objective To investigate the virus-like particles （VLP） immunogenicity of dengue 1 and 2 in monovalent or bivalent.Methods The dengue 1 and 2 VLPs were expressed and purified and used to inject BALB/c mice. Meanwhile inactivate dengue virus 1 and 2 were used as positive controls, and PBS as negative control. The anti-VLPs serum6 antibody titers of mice were detected by ELISA. The levels of cytokines IFN-γ,TNF-α were measured by Quantikine ELISA kit. The amount of CD4＋, CD8＋ in mice splenocytes were measured by flow cytometric analysis. Results Both monovalent and bivalent VLP of dengue 1 and 2 could induce mice to produce certain levels of anti-VLPs serum antibody, but the antibody level of VLP1 group was lower than that of VLP2 group.The antibody level of valant VLP group with DENV2 challenge increase greatly was about 2-3 times of VLP2. After dengue virus challenge, the inactivate DENV1 group and VLP2 group could induce high serum level of IFN-γ. The level of TNF-α in VLP2 group was always high. The level of TNF-ot in bivalent VLP group with DENV2 challenge was higher than with DENV1 challenge. After three times of vaccination, the ratios of CD4~ in all experiment groups were lower than the group of PBS, but the ratios of CD8＋ showed no obvious change, except in the group of inactivate DENV1 showed a little increase, and other groups showed a little decrease. Conclusion Dengue 1 and 2 VLP both in monovalent and bivalent all can induce certain degree of humoral and cellular immunity, and combination of vaccination showed some coordination.