Characterization of proteins present in the biofilm matrix and outer membrane vesicles of Histophilus somni during iron-sufficient and iron-restricted growth: identification of potential protective antigens through in silico analyses
Journal
mBio
Journal Volume
16
Journal Issue
5
ISSN
2150-7511
Date Issued
2025-05-14
Author(s)
Editor(s)
Rappuoli, Rino
Abstract
There is limited efficacy in vaccines currently available to prevent some animal diseases of bacterial origin, such as bovine respiratory disease caused by Histophilus somni. Protective efficacy can potentially be improved if bacterial antigens that are expressed in the host are included in vaccines. During H. somni infection in the bovine host, biofilms become established, and the availability of essential iron is restricted. To investigate further, the protein composition of spontaneously released outer membrane vesicles (OMVs) during iron-sufficient and iron-restricted growth and the proteins expressed in the biofilm matrix were analyzed and compared. Proteomic analysis revealed a dramatic physiological change in H. somni as it transitioned from the planktonic form to the biofilm mode of growth. All transferrin-binding proteins (Tbps) previously identified in H. somni were detected in the OMVs, suggesting that OMVs could induce antibodies to these proteins. Two TbpA-like proteins and seven total proteins were present in the OMVs only when iron was restricted, indicating the expression of these Tbps was differentially regulated. More proteins associated with quorum-sensing (QS) signaling were detected in the biofilm matrix compared with proteins in the OMVs, supporting a link between QS and biofilm formation. Proteins ACA31267.1 (OmpA) and ACA32419.1 (TonB-dependent receptor) were present in the OMV and biofilm matrix and predicted to be potential protective antigens using an immuno-bioinformatic approach. Overall, the results support the development of novel vaccines that contain OMVs obtained from bacteria grown to simulate the in vivo environment, and possibly biofilm matrix, to prevent diseases caused by bacterial pathogens.
Subjects
biofilm matrix
Histophilus somni
iron acquisition
outer membrane vesicles
protective antigen
reverse vaccinology
Publisher
American Society for Microbiology
Type
journal article