Evaluation of Highly Conserved Outer Membrane Proteins as Protective Antigens Against Respiratory Melioidosis.

(), 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 . This led us to explore whether there exists a subset of antigens that are conserved in other pathogenic species which could potentially serve as components of a pan- vaccine. We assessed the proteome of and identified several antigens that are conserved in the 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 respiratory challenge, which supports the idea that these antigens could be candidates for a cross-protective vaccine.