mRNA-LNP Vaccines Targeting SmpA-PLD and OmpK-Omp22 Induce Protective Immunity Against Acinetobacter baumannii

Area of Science:

• Infectious Diseases
• Vaccinology
• Microbiology

Background:

• Acinetobacter baumannii is a critical pathogen causing high mortality and nosocomial outbreaks.
• Multidrug-resistant A. baumannii presents a significant public health threat.
• No approved vaccines currently exist for A. baumannii infections.

Purpose of the Study:

• To develop and evaluate novel mRNA-lipid nanoparticle (LNP) vaccines against Acinetobacter baumannii.
• To assess the immunogenicity and protective efficacy of two distinct mRNA vaccine candidates.

Main Methods:

• Two mRNA vaccines were designed targeting SmpA-PLD and a fusion of OmpK-Omp22.
• mRNA was encapsulated in LNPs and administered to BALB/c mice.
• Humoral and cellular immunity, bacterial burden, inflammation, and survival were assessed in a sepsis model.

Main Results:

• Both mRNA vaccines induced robust immune responses and reduced bacterial burden and inflammation.
• Significant protection against A. baumannii infection was observed in vaccinated mice.
• The OmpK-Omp22 vaccine demonstrated superior efficacy, reducing organ bacterial loads and improving survival.

Conclusions:

• mRNA-LNP vaccine technology is a viable platform for developing A. baumannii therapeutics.
• These vaccines show potential for mitigating acute infections and promoting bacterial decolonization.
• The study paves the way for urgently needed antibacterial vaccines against A. baumannii.