# Evaluation of Highly Conserved Burkholderia pseudomallei Outer Membrane Proteins as Protective Antigens Against Respiratory Melioidosis

## TL;DR

This study identifies conserved proteins in Burkholderia pseudomallei that could help develop a vaccine against melioidosis and related infections.

## Contribution

The study identifies conserved outer membrane proteins in B. pseudomallei that induce cross-protective immunity in mice.

## Key findings

- AuNP-coupled OmpA1 and OmpA2 induced Th1/Th2-balanced immune responses and mucosal immunity in mice.
- Mice immunized with AuNP-OmpA1 or AuNP-OmpA2 were protected against a lethal B. pseudomallei respiratory challenge.
- The identified antigens are conserved in the B. cepacia complex, suggesting potential for a pan-Burkholderia vaccine.

## Abstract

Burkholderia pseudomallei (Bpm), the etiological agent of melioidosis, lacks approved vaccines. However, several candidate vaccines have conferred protection in animal models. Interestingly, some of these vaccines have been shown to induce cross-protective immunity against the closely related species B. mallei. This led us to explore whether there exists a subset of antigens that are conserved in other pathogenic Burkholderia species which could potentially serve as components of a pan-Burkholderia vaccine. We assessed the proteome of Bpm and identified several antigens that are conserved in the B. cepacia complex. To evaluate these antigens, we intranasally immunized mice with three proteins (OmpA1, OmpA2, Pal) coupled to an immunogenic gold nanoparticle (AuNP) platform, resulting in the induction of robust Th1/Th2-balanced responses and mucosal immunity. Animals immunized with AuNP-OmpA1 or AuNP-OmpA2 exhibited protection against a lethal Bpm respiratory challenge, which supports the idea that these antigens could be candidates for a cross-protective vaccine.