嵌合人偏肺病毒(hMPV)表位的重组流感病毒免疫保护效果

目的评价重组嵌合表达人偏肺病毒(hMPV)表位的流感病毒的免疫应答及免疫保护效果。方法用8质粒系统拯救出的在NS基因中嵌合hMPV表位的重组流感病毒免疫BALB/c小鼠,检测其刺激机体产生的针对hMPV和流感病毒的抗体滴度,及脾细胞分泌细胞因子含量。免疫后小鼠用hMPV和流感病毒进行攻击,对攻击后小鼠肺组织和鼻甲骨中病毒含量采用数字PCR方法进行测定,同时对肺组织进行HE染色,评价其对肺部损伤的保护作用。结果重组流感病毒株rFLU/hMPV/B(嵌入了hMPV的B细胞表位)免疫小鼠后,产生了针对hMPV和流感病毒的特异性抗体。rFLU/hMPV/CTL+Th(嵌入了CTL表位/Th细胞表位)免疫小鼠后,产生了针对流感病毒的特异性抗体及hMPV特异的细胞毒性T淋巴细胞反应(IFN-γ分泌增多)。rFLU/hMPV/B和rFLU/hMPV/CTL+Th引起了平衡的Th1/Th2免疫应答。用hMPV和流感病毒攻击重组病毒免疫后小鼠,肺组织病理HE染色结果显示重组病毒免疫后小鼠肺病变明显减轻,肺组织和鼻甲骨中hMPV和流感病毒含量也明显减少。结论重组的2株嵌合有hMPV B细胞表位和CTL表位/Th细胞表位的重组流感病毒株,可刺激机体产生针对hMPV和/或流感病毒体液免疫应答,嵌合有hMPV CTL表位/Th细胞表位的重组流感病毒株还可刺激机体产生hMPV特异性的细胞免疫应答,对hMPV和流感病毒攻击也有一定保护作用,该重组病毒株有潜在疫苗应用价值。

Protection against human metapneumovirus(hMPV)conveyed by influenza virus vectors carrying multiple epitope antigens of hMPV

Objective To evaluate the immune responses and protection against human metapneumovirus(hMPV)conveyed by influenza virus vectors carrying multiple epitope antigens of hMPV.Methods Two recombinant influenza viruses(rFLU/hMPV/B and rFLU/hMPV/CTL+Th)carrying hMPV multi-epitope gene segments in NS gene were generated by reverse genetic techniques of eight-plasmid system.BALB/c mice were immunized intranasally with rFLU/hMPV/B and rFLU/hMPV/CTL+Th twice at a two-week interval.Virus-specific antibody titers and splenocyte cytokines were detected two weeks after the boost immunization.Viral loads in lung tissues and turbinates were detected with digital PCR after the immunized mice were challenged with hMPV and influenza virus.Moreover,HE staining was used to observe lung injuries.Results Specific antibodies against both the influenza virus and hMPV were induced in mice immunized intranasally with rFLU/hMPV/B,while the influenza virus-specific antibody response and hMPV-specific cytotoxic lymphocyte response(significant IFN-γsecretion)were detected in mice immunized with rFLU/hMPV/CTL+Th.Additionally,balanced Th1/Th2 responses were elicited by rFLU/hMPV/B and rFLU/hMPV/CTL+Th.Both rFLU/hMPV/B and rFLU/hMPV/CTL+Th conveyed effective protection against subsequent influenza virus and hMPV challenges with significantly alleviated histopathological damages and reduced viral loads.Conclusions Both rFLU/hMPV/B and rFLU/hMPV/CTL+Th can induce specific humoral immune response against hMPV and/or the influenza virus.Moreover,rFLU/hMPV/CTL+Th can also elicit hMPV-specific CTL immune response.These two recombinant strains can also protect BALB/c mice from the challenges with hMPV and influenza virus,suggesting that they are promising vaccine candidates.