What question did this study set out to answer?

The research aims to identify protein antigens from Acinetobacter baumannii for potential immunotherapy development.

February 14, 2026Open Access

Identification of multiple Acinetobacter baumannii protein antigens as targets for potential immunotherapies using a novel protein microarray screening approach

Puntos clave

The research aims to identify protein antigens from Acinetobacter baumannii for potential immunotherapy development.
Developed an 868-protein microarray targeting conserved A. baumannii proteins.
Probed the microarray with sera from infected mice resulting in IgG response identification.
Selected four protein antigens for further investigation based on antibody recognition.
Conducted passive immunisation experiments to assess protective effects against A. baumannii sepsis.
Identified IgG responses to 66 A. baumannii proteins from infected mouse sera.
Polyclonal IgG to selected antigens improved opsonisation, neutrophil phagocytosis, and membrane attack complex formation.
Passive immunisation reduced sepsis mortality in mice, particularly when targeting two combined antigens.
Protection against infection was dependent on complement and neutrophils, but not macrophages.

Resumen

The World Health Organisation has identified Acinetobacter baumannii as a critical priority antimicrobial resistant (AMR) pathogen for which new therapeutics are needed. Despite this, currently there are no antibody or vaccine candidates in advanced clinical development for A. baumannii . To help address this, we designed a protein microarray approach to identify multiple A. baumannii protein antigens for further investigation as potential targets for vaccination or an antibody therapy. An 868-protein microarray was constructed containing mainly highly conserved A. baumannii proteins, and was enriched for those predicted to be surface localised and for which the corresponding gene is highly expressed during culture in ex vivo human serum. Probing the protein microarray with sera obtained from mice after non-lethal infection with multiple different A. baumannii strains identified IgG responses to 66 proteins. Four proteins (three previously poorly described outer membrane proteins and BamA, a known protective vaccine antigen selected as a positive control) were selected for further investigation. Polyclonal rabbit IgG to all four protein antigens recognised multiple clinical AMR A. baumannii strains, and for selected strains promoted opsonisation with IgG and complement, improved neutrophil phagocytosis, and increased membrane attack complex formation. Passive immunisation with polyclonal IgG to each antigen partially protected mice against A. baumannii sepsis, and a combination of polyclonal to two antigens completely protected against A. baumannii murine sepsis. Repeating passive immunisation experiments in mice depleted of complement, neutrophils or tissue macrophages demonstrated protection against systemic infection was dependent on complement and neutrophils but not macrophages. Overall, the data demonstrate that our protein microarray is a novel approach that can rapidly identify multiple new protein antigens as potential antibody targets for preventing or treating AMR bacterial infections.

Me gusta

Guardar

Ver artículo completo