Venkatesan Malabi M, Hartman Antoinette B, Newland John W, Ivanova Vessela S, Hale Thomas L, McDonough Marie, Butterton Joan
Department of Enteric Infections, Division of Communicable Diseases and Immunology, Walter Reed Army Institute of Research, Silver Spring, Maryland 20910, USA.
Infect Immun. 2002 Jun;70(6):2950-8. doi: 10.1128/IAI.70.6.2950-2958.2002.
WRSd1 is a Shigella dysenteriae 1 vaccine containing deletions of the virG(icsA) gene required for intercellular spreading and a 20-kb chromosomal region encompassing the Shiga toxin genes (stxAB). WRSd1 was constructed from S. dysenteriae 1 strain 1617 that was originally isolated during the 1968 to 1969 epidemic of Shiga dysentery in Guatemala. The virG(icsA) deletion was constructed from a streptomycin-resistant (Str(r)) mutant of 1617 by a filter mating procedures using a virG(icsA) deletion derivative, pDeltavirG2. A colony that was invasive for HeLa cells and negative for the virG(icsA) gene by Southern blotting was grown anaerobically on plates containing chlorate for selection of resistant colonies that had lost the entire Shiga toxin gene. A virG(icsA) stxAB Str(r) mutant selected from the chlorate plates was designated WRSd1. This candidate vaccine was evaluated for safety, immunogenicity, and protective efficacy using the guinea pig keratoconjunctivitis model. WRSd1 was Sereny negative, and two applications of this strain to the cornea elicited a significant protective immune response against the S. dysenteriae 1 O antigen. Vaccination with WRSd1 conferred protection against challenge with each of three virulent S. dysenteriae 1 strains. Since a vaccine protecting against multiple Shigella species is required for most areas where Shigella is endemic, protection studies using a combination vaccine of Shigella sonnei vaccine strain WRSS1, Shigella flexneri 2a vaccine strain SC602, and WRSd1 were also performed. Guinea pigs vaccinated with a mixture of equal amounts of the three vaccine strains were protected against challenge with each of the homologous virulent strains. Unlike WRSS1 and SC602, however, the level of protection afforded by WRSd1 in a combination vaccine was lower than the protection elicited by a pure culture. A current Good Manufacturing Practice product of WRSd1 given intragastrically to rhesus monkeys proved safe and immunogenic.
WRSd1是一种痢疾志贺氏菌1型疫苗，它缺失了细胞间传播所需的virG(icsA)基因以及包含志贺毒素基因（stxAB）的20 kb染色体区域。WRSd1由痢疾志贺氏菌1型菌株1617构建而成，该菌株最初于1968年至1969年危地马拉志贺痢疾流行期间分离得到。virG(icsA)缺失是通过使用virG(icsA)缺失衍生物pDeltavirG2，采用滤膜交配程序从1617的链霉素抗性（Str(r)）突变体构建而来。通过Southern印迹法检测，对HeLa细胞具有侵袭性且virG(icsA)基因为阴性的菌落，在含有氯酸盐的平板上厌氧培养，以筛选丢失整个志贺毒素基因的抗性菌落。从氯酸盐平板上筛选出的virG(icsA) stxAB Str(r)突变体被命名为WRSd1。使用豚鼠角膜结膜炎模型对该候选疫苗的安全性、免疫原性和保护效力进行了评估。WRSd1的Sereny试验为阴性，将该菌株两次接种到角膜上可引发针对痢疾志贺氏菌1型O抗原的显著保护性免疫反应。用WRSd1疫苗接种可对三种强毒株痢疾志贺氏菌1型中的每一种攻击提供保护。由于在志贺氏菌流行的大多数地区都需要一种能预防多种志贺氏菌的疫苗，因此还进行了使用宋内志贺氏菌疫苗株WRSS1、福氏志贺氏菌2a疫苗株SC602和WRSd1的联合疫苗的保护研究。用等量的三种疫苗株混合物接种的豚鼠对每种同源强毒株的攻击都有保护作用。然而，与WRSS1和SC602不同的是，WRSd1在联合疫苗中提供的保护水平低于纯培养物引发的保护作用。给恒河猴胃内接种符合现行药品生产质量管理规范的WRSd1产品，证明是安全且具有免疫原性的。
