Salmonella Typhi is an exclusive human pathogen that causes typhoid fever. Typhoid toxin is a S. Typhi virulence factor that can reproduce most of the typhoid fever symptoms in experimental animals. Toxicity depends on toxin binding to terminally sialylated glycans on surface glycoproteins. Human glycans are unusual because of the lack of CMAH, which in other mammals converts N-acetylneuraminic acid (Neu5Ac) to N-glycolylneuraminic acid (Neu5Gc). Here, we report that typhoid toxin binds to and is toxic toward cells expressing glycans terminated in Neu5Ac (expressed by humans) over glycans terminated in Neu5Gc (expressed by other mammals). Mice constitutively expressing CMAH thus displaying Neu5Gc in all tissues are resistant to typhoid toxin. The atomic structure of typhoid toxin bound to Neu5Ac reveals the structural bases for its binding specificity. These findings provide insight into the molecular bases for Salmonella Typhi's host specificity and may help the development of therapies for typhoid fever.
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http://dx.doi.org/10.1016/j.cell.2014.10.057 | DOI Listing |
Vet Res
January 2025
College of Veterinary Medicine, Jeonbuk National University, Iksan Campus, Iksan, 54596, Republic of Korea.
Fowl typhoid (FT) poses a significant threat to the poultry industry and can cause substantial economic losses, especially in developing regions. Caused by Salmonella Gallinarum (SG), vaccination can prevent FT. However, existing vaccines, like the SG9R strain, have limitations, including residual virulence and potential reversion of pathogenicity.
View Article and Find Full Text PDFPLoS Negl Trop Dis
November 2024
Department of Medical Microbiology, College of Medicine and Health Sciences, University of Gondar, Gondar, Ethiopia.
Gut Microbes
November 2024
College of Veterinary Medicine, Southwest University, Beibei, Chongqing, China.
Non-typhoidal (NTS) is a major global foodborne pathogen that poses a major public health concern worldwide, and no vaccines are available for protecting against infection of multiple serotypes, therefore, the development of vaccines to provide broad protection is valuable. In this work, we aimed to regulate lipopolysaccharide (LPS) synthesis of live for exposing conserved protein antigens on the outer membrane while maintaining smooth LPS patterns to keep their original ability to invade host cells for inducing cross-protection against infection of multiple serotypes. We generated a series of mutants defective in genes to affect the length of LPS.
View Article and Find Full Text PDFSci Rep
November 2024
Laboratorio de Referencia Nacional de Bacteriología Clínica, Instituto Nacional de Salud, Lima, Peru.
Nat Commun
October 2024
Vaccine Branch, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD, USA.
Systemic vaccination of macaques with V1-deleted (ΔV1) envelope immunogens reduce the risk of SIV acquisition by approximately 60%, with protective roles played by V2-specific ADCC and envelope-specific mucosal IL-17NKp44 innate lymphoid cells (ILCs). We investigated whether increased mucosal responses to V2 benefit vaccine efficacy by delivering oral nanoparticles (NPs) that release V2-scaffolded on Typhoid Toxin B (TTB) to the large intestine. Strikingly, mucosal immunization of male macaques abrogated vaccine efficacy with control TTB or empty NPs, but vaccine efficacy of up to 47.
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