Fig. 1From: Effect of deletion of gene cluster involved in synthesis of Enterobacterial common antigen on virulence and immunogenicity of live attenuated Salmonella vaccine when delivering heterologous Streptococcus pneumoniae antigen PspAECA operon deletion in S. Typhimurium χ3761 a Map of the ECA operon. b Schematic strategy for deletion of the ECA operon by allelic exchange using suicide vectors; the whole ECA operon from wecA to wecG was deleted. c ECA operon deficiency mutation identification by PCR amplification. Primer pairs for Doperon-1F/Doperon-2R were used to amplify the ECA operon using the ECA-deficient S. Typhimurium mutant χ12357 (lane 1) and the wide type χ3761 (lane 2) as the PCR template. A PCR product of approximately 800 bp was observed for χ12357, but no bands were observed for wild type S. Typhimurium χ3761. d Detection of ECA using ECA-specific mAb898 antibody by western blotting. The wide type S. Typhimurium χ3761 could produce ECA, but the ECA-deficient Salmonella strain χ12357 lost the ability to produce ECABack to article page