Live, attenuated Salmonella typhimurium vectoring Campylobacter antigens

Area of Science:

• Microbiology
• Vaccinology
• Immunology

Background:

• Salmonella Typhimurium is a common cause of bacterial gastroenteritis.
• Developing effective vaccines against enteric pathogens is crucial for public health.
• PEB1 is a potential antigen for vaccines targeting enteric infections.

Purpose of the Study:

• To evaluate the immunogenicity of live attenuated Salmonella Typhimurium strains expressing PEB1.
• To assess the efficacy of these strains in inducing protective immunity against Campylobacter jejuni.

Main Methods:

• Construction of three Salmonella Typhimurium strains expressing PEB1-ss using different plasmid systems (pBR-asd, arabinose-based runaway, PEB1::HlyA fusion).
• Evaluation of serum IgG responses specific for PEB1-ss via Western blot analysis.
• Assessment of protection against oral Campylobacter jejuni challenge in mice.

Main Results:

• pBR-derived and runaway plasmids induced high seroconversion rates (100% and 90%) for PEB1-ss specific IgG.
• The PEB1-ss::HlyA fusion plasmid showed lower immunogenicity (20% seroconversion).
• Despite significant IgG induction, no protection against Campylobacter jejuni challenge was observed.

Conclusions:

• Live attenuated Salmonella Typhimurium expressing PEB1-ss can elicit robust systemic IgG responses.
• The delivery method of PEB1-ss influences its immunogenicity.
• Current vaccine strategies using these strains do not confer protection against Campylobacter jejuni infection.