Analysis of Salmonella Typhi Pathogenesis in a Humanized Mouse Model

Area of Science:

• Infectious Diseases
• Immunology
• Microbiology

Background:

• Salmonella enterica serovar Typhi causes typhoid fever but lacks a suitable animal model for pathogenesis studies.
• Previous research efforts were hindered by the absence of tractable models to investigate human-restricted pathogens.

Purpose of the Study:

• To develop and validate a humanized mouse model for studying Salmonella Typhi pathogenesis.
• To enable the investigation of molecular mechanisms of typhoid fever in a relevant in vivo system.

Main Methods:

• Utilized genetically modified mice engrafted with human CD34+ stem cells (CD34+ Hu-NSG mice).
• Infected CD34+ Hu-NSG mice with Salmonella Typhi.
• Constructed and analyzed a transposon-directed insertion site sequencing library for S. Typhi.

Main Results:

• CD34+ Hu-NSG mice developed lethal systemic Salmonella Typhi infections dependent on human hematopoietic cells.
• The model recapitulated key immunological and pathological features of human typhoid fever.
• The model facilitated the identification of bacterial genetic determinants of S. Typhi virulence.

Conclusions:

• The CD34+ humanized mouse model is a valuable tool for studying human-restricted pathogens like Salmonella Typhi.
• This model overcomes limitations of previous animal models, enabling deeper understanding of typhoid fever.
• It supports the discovery of bacterial virulence factors and potential therapeutic targets.