Cell-associated flagella enhance the protection conferred by mucosally-administered attenuated Salmonella Paratyphi A vaccines.
Cell-associated flagella enhance the protection conferred by mucosally-administered attenuated Salmonella Paratyphi A vaccines.
复制标题
DOI：
10.1371/journal.pntd.0001373
复制
发表时间：
2011-11
影响因子：
3.8
通讯作者：
Levine MM
中科院分区：
文献类型：
--
作者：
Gat O;Galen JE;Tennant S;Simon R;Blackwelder WC;Silverman DJ;Pasetti MF;Levine MM
甲型副伤寒的病原体--耐药的甲型副伤寒沙门氏菌A在亚洲流行地区和旅行者中造成了一个新的公共卫生困境，因为没有获得许可的疫苗。为了开发甲型副伤寒沙门氏菌疫苗，我们通过比较细胞相关鞭毛和减毒株表达的出口鞭毛蛋白亚基，探讨了鞭毛作为潜在保护性抗原的作用。甲型副伤寒沙门氏菌ATCC 9150株首先被删除了染色体上的Guaba基因座，产生了CVD1901。然后在fld(CVD 1901D)或flgK(CVD 1901K)中进一步设计染色体缺失，导致未聚合的flc的输出，而不影响其整体表达。用一种新的小鼠LD50模型检测得到的同基因菌株的毒力，以适应人-宿主限制性甲型副伤寒沙门氏菌。然后用小鼠鼻内模型检测减毒株的免疫原性，然后用野生型ATCC 9150进行腹腔攻击。与输出鞭毛单体的突变体CVD 1901K(30%VE)或CVD1901D(47%VE)相比，表达细胞相关鞭毛的CVD 1901菌株鼻腔免疫小鼠可提供更好的保护(疫苗效力[VE]，90%)。CVD1901通过其细胞附着的鞭毛诱导的更好的保护作用与Flc特异性抗体的IgG2a：IgG1比率增加和吞噬细胞能力增强有关。我们的结果清楚地表明，表达细胞相关蛋白的疫苗诱导的吞噬细胞对甲型副伤寒沙门氏菌的清除增强，可能是疫苗诱导的甲型副伤寒沙门氏菌在体内的保护作用。我们推测，由出口的Flc诱导的过量的IgG1抗flic抗体可能与IgG2a亚型竞争，并阻断与特定的吞噬细胞Fc受体的结合，而Fc受体是清除甲型副伤寒沙门氏菌感染的关键。甲型副伤寒沙门氏菌是一种引起全身性疾病的病原体，其特点是严重的并发症，如果不治疗，死亡率会很高。甲型副伤寒沙门氏菌的致病机制和疫苗的研究一直是极具挑战性的，因为甲型副伤寒沙门氏菌是受人类宿主限制的，目前还没有合适的动物模型。由于目前还没有获得许可的疫苗来预防由这种微生物引起的副伤寒，我们的研究是开发和改进针对副伤寒A的疫苗的开创性尝试。我们使用了活的减毒菌株，允许通过自然感染途径在体内呈现细菌抗原，而不会出现与抗原生产和亚单位疫苗纯化相关的并发症。为了确定对感染的保护性免疫，我们开发了一个小鼠模型，可以评估疫苗的效力。我们使用我们的系统来检查一种主要的沙门氏菌抗原--鞭毛的保护能力。由于其独特的免疫原性，鞭毛被认为是主要的免疫介质，但其保护作用存在争议。我们清楚地表明，与出口FLIC单体的菌株相比，由粘膜注射的减毒细菌活疫苗提供的细胞相关鞭毛蛋白提供了更好的保护，并讨论了可能的免疫机制。
Antibiotic-resistant Salmonella enterica serovar Paratyphi A, the agent of paratyphoid A fever, poses an emerging public health dilemma in endemic areas of Asia and among travelers, as there is no licensed vaccine. Integral to our efforts to develop a S. Paratyphi A vaccine, we addressed the role of flagella as a potential protective antigen by comparing cell-associated flagella with exported flagellin subunits expressed by attenuated strains. S. Paratyphi A strain ATCC 9150 was first deleted for the chromosomal guaBA locus, creating CVD 1901. Further chromosomal deletions in fliD (CVD 1901D) or flgK (CVD 1901K) were then engineered, resulting in the export of unpolymerized FliC, without impairing its overall expression. The virulence of the resulting isogenic strains was examined using a novel mouse LD50 model to accommodate the human-host restricted S. Paratyphi A. The immunogenicity of the attenuated strains was then tested using a mouse intranasal model, followed by intraperitoneal challenge with wildtype ATCC 9150. Mucosal (intranasal) immunization of mice with strain CVD 1901 expressing cell-associated flagella conferred superior protection (vaccine efficacy [VE], 90%) against a lethal intraperitoneal challenge, compared with the flagellin monomer-exporting mutants CVD 1901K (30% VE) or CVD 1901D (47% VE). The superior protection induced by CVD 1901 with its cell-attached flagella was associated with an increased IgG2a∶IgG1 ratio of FliC-specific antibodies with enhanced opsonophagocytic capacity. Our results clearly suggest that enhanced anti-FliC antibody-mediated clearance of S. Paratyphi A by phagocytic cells, induced by vaccines expressing cell-associated rather than exported FliC, might be contributing to the vaccine-induced protection from S. Paratyphi A challenge in vivo. We speculate that an excess of IgG1 anti-FliC antibodies induced by the exported FliC may compete with the IgG2a subtype and block binding to specific phagocyte Fc receptors that are critical for clearing an S. Paratyphi A infection. Salmonella enterica serovar Paratyphi A is a pathogen that causes a systemic disease that is marked by serious complications and, if untreated, high mortality. The study of S. Paratyphi A pathogenesis and vaccine development has been extremely challenging since S. Paratyphi A is human host-restricted and no appropriate animal model exists. Since there is currently no licensed vaccine to prevent paratyphoid fever caused by this organism, our study represents a pioneering attempt to develop and refine a vaccine against S. Paratyphi A. We employed live attenuated strains which allow in vivo presentation of bacterial antigens via the natural route of infection, without the complications associated with antigen production and purification for subunit vaccines. For determining protective immunity against infection, we developed a mouse model that allowed evaluation of vaccine efficacy. We used our system to examine the protective capacity of a major Salmonella antigen, the flagellum. Due to its unique immunogenic properties, the flagellum is considered a major immune mediator, but its role in protection is controversial. We clearly show that cell-associated flagellar protein, presented by mucosally administered attenuated bacterial live vaccines, provides superior protection when compared to strains exporting FliC monomers, and we discuss possible mechanisms of immunity.
登录
查看更多内容
DOI：
10.1073/pnas.91.18.8631
发表时间：
1994-08-30
影响因子：
11.1
作者：
HARSHEY, RM;MATSUYAMA, T
通讯作者：
MATSUYAMA, T
影响因子：
30.5
作者：
Franchi, Luigi;Amer, Amal;Nunez, Gabriel
通讯作者：
Nunez, Gabriel
DOI：
10.1073/pnas.120163297
发表时间：
2000-06-06
影响因子：
11.1
作者：
Datsenko, KA;Wanner, BL
通讯作者：
Wanner, BL
DOI：
10.1073/pnas.0605200103
发表时间：
2006-08-15
影响因子：
11.1
作者：
Feuillet, Vincent;Medjane, Samir;Alexopoulou, Lena
通讯作者：
Alexopoulou, Lena
影响因子：
3.1
作者：
Honko, AN;Mizel, SB
通讯作者：
Mizel, SB