Identification of immunogenic outer membrane proteins and evaluation of their protective efficacy against Stenotrophomonas maltophilia

Abstract

BackgroundStenotrophomonas maltophilia (S. maltophilia) is an emerging global multiple-drug-resistant organism. It becomes increasingly challenging to treat S. maltophilia infection effectively. Novel therapeutic and preventive approaches targeting S. maltophilia infection are still lacking. This study aims to isolate outer membrane proteins (Omps) from S. maltophilia and use immunoproteomic technology to identify potential vaccine candidates of Omps against S. maltophilia infections.MethodsOmps from S. maltophilia culture were separated by two-dimensional electrophoresis and identified by matrix-assisted laser desorption/ionization time of flight mass spectrometry and nano liquid chromatography coupled fourier transform ion cyclotron resonance tandem mass spectrometry. Recombinant Omps were prepared and used to immunize mice, and the potency of mouse anti-Omp serum was tested in opsonophagocytic killing assay (OPKA). The effects of immunization with recombinant Omp on blood and tissue bacterial loads in a mouse model of S. maltophilia-induced infection were analyzed.ResultsOuter membrane protein A (OmpA) and Smlt4123 were identified by mass spectrometry. Mouse anti-Smlt4123 serum significantly reduced the bacterial counts in healthy individuals’ blood in OPKA (P < 0.05) but mouse anti-OmpA serum did not. Enzyme-linked immunosorbent assay revealed that the antibody subtype of mouse anti-Smlt4123 antibody was IgG1. Eight hours after an intraperitoneal challenge with S. maltophilia, the bacterial loads in mouse blood were significantly lower in the mice receiving immunization with recombinant Smlt4123 than in the control mice receiving no immunization (P < 0.05), whereas the bacterial loads in other organs, such as the liver, spleen, lung, and kidney were similar in the two groups.ConclusionsThe results revealed that the immunoproteomic approach was an efficient way to screen the immunogenic protein of Stenotrophomonas maltophilia. Moreover, the recombinant Smlt4123 had potential to protect mice from bacteremia caused by S. maltophilia in the early stages.Electronic supplementary materialThe online version of this article (10.1186/s12879-018-3258-7) contains supplementary material, which is available to authorized users.

Intranasal immunization with recombinant outer membrane protein A induces protective immune response against Stenotrophomonas maltophilia infection

“…In our preliminary study, we used immunoproteomic approach to discover that outer membrane protein A (OmpA) was a strong immunogenic antigen and could be a good vaccine candidate against S . maltophilia infection [19]. OmpA and OmpA-like proteins, such as OmpA in Escherichia coli ( E .…”

Characterization of Co-Stimulatory Ligand CD80/86 and Its Effect as a Molecular Adjuvant on DNA Vaccine Against Vibrio anguillarum in Flounder (Paralichthys olivaceus)

“…V. anguillarum is a serious pathogenic bacteria in aquaculture that caused massive mortality of marine fish, bivalves, and crustaceans ( 55 , 56 ). More evidence proved that the outer membrane proteins of pathogenic bacteria are highly immunogenic and provide immune protection against pathogenic bacteria in fish as a vaccine ( 57 – 59 ). In our previous research, multiple immunogenic proteins have been identified in V. anguillarum including VirA, CheR, FlaC, OmpK, OmpR, Hsp33, VAA, Groel, OmpU, PteF, and SpK ( 60 , 61 ); the OmpK and OmpR as subunit vaccines induced the secretion of specific antibodies and immunoprotection with an RPS of 62.16% and 64.86%, respectively, against V. anguillarum .…”