Work

Host TGF-β signalling facilitates Vi-capsule mediated adaptive immune evasion and vertical transmission of Salmonella Typhi in Caenorhabditis elegans

Year: 2025

Type: article

Abstract: Bacterial infections trigger robust host immune responses, while pathogens concurrently adapt to enhance survival within the host. In our previous study, we observed 24 h of Salmonella Typhi infection in Caenorhabditis elegans colonized the body of the host and also vertically transmitted to their F1 offspring generation. This study investigates host interaction-mediated modulation in S. typhi physiology and virulence, focusing on host-derived strains from initial infection (CeP0-ST) and vertically transmitted F1 progeny (CeF1-ST), compared to the wild-type unexposed strain (WT-ST). We employed C. elegans lifespan assays, bacterial colonization, morphology, motility, gene expression, ROS estimation, and infection models using immune pathway mutants. CeP0-ST and CeF1-ST exhibited increased infectivity, faster mortality, and enhanced colonization, accompanied by reduced cell size, motility, and lipopolysaccharide (LPS)-mediated immunogenicity. This was evidenced by downregulation of fliC , ompC , ompF , and SPI-1 encoded Type III Secretion System (T3SS-1) genes ( sipA , avrA , sopE ). Upregulation of Vi-capsular antigen genes ( tviD , tviA , viaB ) suggested immune evasion, which was supported by improved host survival upon Vi-negative Ty21a strain infection. Among various C. elegans immune pathway mutants, the TGF-β pathway mutant [ sma-6 (−)] showed altered pathogen modulation, with reduced Vi expression and increased T3SS gene expression in derived strains. Suppressed host immune gene expression during WT-derived infections, but increased expression during sma-6 (−)-derived infections, suggests a role for TGF-β signalling in driving pathogen adaptation. These findings highlight that host interaction promotes S. typhi immune evasion via Vi-antigen expression, potentially regulated by host TGF-β signalling, and that vertical transmission of adapted strains facilitates long-term persistence.

Source: The Cell Surface

DOI: 10.1016/j.tcsw.2025.100163

Authors: Bynedi Seshadhri Chinna Mounish, Ravichandran Monisha, Krishnaswamy Balamurugan

Institution: Alagappa University

Language: English

Topic: Salmonella and Campylobacter epidemiology

Subfield: Food Science

Field: Agricultural and Biological Sciences

Domain: Life Sciences

SDG: Good health and well-being

Open Access status: gold

Estimated APC paid: $2,530