Analysis of Type II Secretion of Recombinant Pneumococcal PspA and PspC in a Salmonella enterica Serovar Typhimurium Vaccine with Regulated Delayed Antigen Synthesis
Analysis of Type II Secretion of Recombinant Pneumococcal PspA and PspC in a Salmonella enterica Serovar Typhimurium Vaccine with Regulated Delayed Antigen Synthesis
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DOI：
10.1128/iai.01623-07
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发表时间：
2008-05
影响因子：
3.1
通讯作者：
Wei Xin;S. Wanda;Yuhua Li;Shifeng Wang;Hua Mo;R. Curtiss
中科院分区：
文献类型：
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作者：
Wei Xin;S. Wanda;Yuhua Li;Shifeng Wang;Hua Mo;R. Curtiss
重组减毒沙门氏菌疫苗（RASV）已被广泛用于表达和递送异源抗原至宿主粘膜组织。当抗原分泌到周质或细胞外区室时，免疫应答可以大大增强。实现这一点的最常见方法是通过将抗原融合到分泌信号序列。寻找最佳信号序列通常凭经验完成。为了促进这一过程，我们构建了一系列质粒表达载体，每个载体含有不同的II型信号序列。我们通过将两种不同的抗原，肺炎球菌表面蛋白A（PspA）和肺炎球菌表面蛋白C（PspC）的α-螺旋结构域融合到Ptrc启动子控制下的Asd+质粒上的β-内酰胺酶（bla SS）、ompA和phoA的信号序列以及β-内酰胺酶（bla SS+CT）的信号序列和C-末端肽，来评估这些载体的效用。对菌株的表达水平、亚细胞抗原定位以及引发抗原特异性免疫应答的能力和对小鼠中肺炎链球菌攻击的保护进行表征。对每种蛋白质的免疫反应取决于所使用的信号序列。携带bla SS-pspA和bla SS+CT-pspC融合体的菌株分别产生最大量的分泌PspA和PspC，并诱导最高的血清IgG滴度，尽管测试的所有融合蛋白都诱导了一定水平的抗原特异性IgG反应。与血清抗体应答一致，表达bla SS-pspA和bla SS+CT-pspC融合体的RASV诱导针对S.肺炎攻毒。
ABSTRACT Recombinant attenuated Salmonella vaccines (RASVs) have been used extensively to express and deliver heterologous antigens to host mucosal tissues. Immune responses can be enhanced greatly when the antigen is secreted to the periplasm or extracellular compartment. The most common method for accomplishing this is by fusion of the antigen to a secretion signal sequence. Finding an optimal signal sequence is typically done empirically. To facilitate this process, we constructed a series of plasmid expression vectors, each containing a different type II signal sequence. We evaluated the utilities of these vectors by fusing two different antigens, the α-helix domains of pneumococcal surface protein A (PspA) and pneumococcal surface protein C (PspC), to the signal sequences of β-lactamase (bla SS), ompA, and phoA and the signal sequence and C-terminal peptide of β-lactamase (bla SS+CT) on Asd+ plasmids under the control of the Ptrc promoter. Strains were characterized for level of expression, subcellular antigen location, and the capacity to elicit antigen-specific immune responses and protection against challenge with Streptococcus pneumoniae in mice. The immune responses to each protein differed depending on the signal sequence used. Strains carrying the bla SS-pspA and bla SS+CT-pspC fusions yielded the largest amounts of secreted PspA and PspC, respectively, and induced the highest serum IgG titers, although all fusion proteins tested induced some level of antigen-specific IgG response. Consistent with the serum antibody responses, RASVs expressing the bla SS-pspA and bla SS+CT-pspC fusions induced the greatest protection against S. pneumoniae challenge.