Salih O, Remaut H, Waksman G, Orlova EV. fimbrial operons. Most of the fimbriae encoded by these operons are not produced under laboratory conditions but are likely to be synthesized expression technology (IVET) strategy to identify four fimbrial operons, that are expressed in the spleen. When any three of these operons were deleted, the strain retained wild-type virulence. However, when all four operons were deleted, the resulting strain was completely attenuated, indicating that these four fimbriae play functionally redundant roles critical for virulence. In mice, oral doses of as low as 1 105?CFU of the strain with four fimbrial operons deleted provided 100% protection against challenge with 1 109?CFU of wild-type vaccine strain to deliver a guest antigen. We modified one of our established attenuated vaccine strains, 9088, to delete three fimbrial operons while the fourth operon was constitutively expressed. Each derivative was modified to express the antigen PspA. Strains that constitutively expressed or elicited a strong Th1 response with significantly greater levels of anti-PspA serum IgG and greater protective efficacy than strains carrying or deletions. The isogenic strain in which all four operons were deleted generated the lowest anti-PspA levels and did not protect against challenge with virulent virulence and immunogenicity. expression, recombinant attenuated vaccine IMPORTANCE is the leading cause of bacterial food-borne infection in the United States. S.?Typhimurium is capable of producing up to 13 distinct surface structures called fimbriae that presumably mediate its adherence to surfaces. The roles of most of these fimbriae in disease are unknown. Identifying fimbriae produced during infection will provide important insights into how these bacterial structures contribute to disease and potentially induce protective immunity to infection. We identified four fimbriae that are produced during infection. Deletion of all four of these fimbriae results GSK369796 in a significant reduction in virulence. We explored ways in which the expression of these fimbriae may be exploited for use in recombinant vaccine strains and found that production of Saf and Stc fimbriae are GSK369796 important for generating a strong immune response against GSK369796 a vectored antigen. This work provides new insight into the role of fimbriae in disease and their potential for improving the efficacy GSK369796 of serovar Typhimurium contains 13 fimbrial operons, ((2,C4). While the functions of a few of these fimbriae, including type 1 fimbriae (Fim), have been characterized (1, 5), the functions of most fimbriae are unknown. This is due, in part, to the fact that only type 1 and Agf fimbriae are produced under laboratory growth conditions (6). Type 1 fimbriae are produced when cells are grown at 37C, and Agf fimbriae are produced when cells are grown at 26C (7). While it is possible that some of these other fimbriae may be required for life outside a host (8), it is likely that Mouse monoclonal antibody to AMACR. This gene encodes a racemase. The encoded enzyme interconverts pristanoyl-CoA and C27-bile acylCoAs between their (R)-and (S)-stereoisomers. The conversion to the (S)-stereoisomersis necessary for degradation of these substrates by peroxisomal beta-oxidation. Encodedproteins from this locus localize to both mitochondria and peroxisomes. Mutations in this genemay be associated with adult-onset sensorimotor neuropathy, pigmentary retinopathy, andadrenomyeloneuropathy due to defects in bile acid synthesis. Alternatively spliced transcriptvariants have been described many play an as yet undiscovered role in host interactions. The operon encodes thin aggregative fimbriae (9) in (11). Thin aggregative fimbriae (hereafter Agf fimbriae) and curli are not produced at 37C (11). Production of Agf fimbriae is typically induced in laboratory settings by growing cells at 26C. Pef fimbriae mediate adherence to the murine small intestine and are required for fluid accumulation in infant mice. Expression of genes is regulated by DNA methylation (12). Stf fimbriae share homology with MR/P GSK369796 fimbriae of and Pap fimbriae (13), and expression of is induced during infection of bovine ileal loops (14). Long polar fimbriae (Lpf) are important for colonization of Peyers patches in mice by mediating adherence to M cells (5). Lpf also plays a role in the early stages of biofilm formation on host epithelial cells (15) and is involved in intestinal persistence (16). Lpf synthesis is regulated by an on-off switch mechanism (phase variation) to avoid host immune responses (17). Some fimbriae have been shown to serve functions beyond those required for interactions at the intestinal mucosal surface. For example, the Agf fimbriae are required for biofilm formation in the gallbladder (18,.
Salih O, Remaut H, Waksman G, Orlova EV
