Yılmaz Çiğdem, Apak Aycan, Özcengiz Erkan, Özcengiz Gülay
Department of Biological Sciences, Middle East Technical University, Ankara, Turkey.
Department of Biology, Amasya University, Amasya, Turkey.
Microbiol Immunol. 2016 Nov;60(11):717-724. doi: 10.1111/1348-0421.12445.
Whooping cough (pertussis) is a highly contagious respiratory infection caused by Bordetella pertussis. Although availability of effective pertussis vaccines reportedly decreases the incidence of the disease, B. pertussis circulation in populations has not been eliminated. Thus, it is necessary to find new protein candidates with greater immune protective capacities than the currently available acellular pertussis vaccines. In this study, iron superoxide dismutase (FeSOD) gene (sodB) was cloned, expressed in Escherichia coli and recombinant FeSOD protein thence purified. The recombinant protein (rFeSOD) was formulated with aluminum hydroxide (Alum) or monophosphoryl lipid A (MPLA) and injected intraperitoneally to immunize mice, after which IgG1, IgG2a and IFN-γ titers were measured to assess humoral and cellular responses, respectively, to these immunizations. The extent of bacterial colonization in lungs of intranasally challenged mice was determined 5, 8 and 14 days post-challenge. IgG1 and IgG2a responses were significantly stronger in mice that had been immunized with rFeSOD-MPLA than in those that had received rFeSOD-Alum (P < 0.05). Additionally, IgG2a titers were higher in mice vaccinated with recombinant protein FeSOD (rFeSOD) formulated with MPLA, especially after the second immunization. Immunization with rFeSOD-MPLA also provided a modest, but significant decrease in bacterial counts in lungs of mice (P < 0.05). Antigen specific-IFN-γ responses were significantly stronger in the group vaccinated with rFeSOD-MPLA, which could account for the lower bacterial counts. These findings suggest that rFeSOD protein formulated with MPLA has potential as an acellular pertussis vaccine candidate component.
百日咳是由百日咳博德特氏菌引起的一种高度传染性呼吸道感染。尽管据报道有效的百日咳疫苗的使用降低了该疾病的发病率，但百日咳博德特氏菌在人群中的传播尚未消除。因此，有必要寻找比目前可用的无细胞百日咳疫苗具有更强免疫保护能力的新蛋白质候选物。在本研究中，克隆了铁超氧化物歧化酶（FeSOD）基因（sodB），在大肠杆菌中表达并纯化了重组FeSOD蛋白。将重组蛋白（rFeSOD）与氢氧化铝（Alum）或单磷酰脂质A（MPLA）配制，腹腔注射免疫小鼠，然后测量IgG1、IgG2a和IFN-γ滴度，分别评估这些免疫接种后的体液和细胞反应。在鼻内攻击小鼠后5、8和14天测定肺部细菌定植程度。用rFeSOD-MPLA免疫的小鼠的IgG1和IgG2a反应明显强于接受rFeSOD-Alum的小鼠（P < 0.05）。此外，用MPLA配制的重组蛋白FeSOD（rFeSOD）免疫的小鼠的IgG2a滴度更高，尤其是在第二次免疫后。用rFeSOD-MPLA免疫也使小鼠肺部的细菌数量适度但显著减少（P < 0.05）。用rFeSOD-MPLA接种的组中抗原特异性IFN-γ反应明显更强，这可以解释细菌数量较低的原因。这些发现表明，用MPLA配制的rFeSOD蛋白有潜力作为无细胞百日咳疫苗候选成分。
