Immunoreactive antigens recognized in serum samples from mice intranasally immunized with Porphyromonas gingivalis outer membrane vesicles.
Outer membrane vesicles (OMVs) of the periodontopathic bacterium Porphyromonas gingivalis contain a wide range of virulence factors including lipopolysaccharide (LPS), fimbriae and gingipains. We have recently reported strong immunogenicity of OMVs using an intranasal vaccine mouse model. In the present study, we performed sub-immunoproteome analysis of OMV-immunized mouse serum samples from six different mice in order to identify immunodominant antigens. The combination of two-dimensional (2D) gel electrophoresis and mass spectrometry analysis identified OMV proteins of 53 spots on a 2D map, and it was notable that OMV proteins were largely distributed within a low pH range, in marked contrast to the ubiquitous distribution of outer membrane proteins. Western blot using the six serum samples after 2D electrophoresis revealed that all showed immunoreactivity to some diffuse signals at extremely low pH, which was similar to the distribution of immunoreactive signals when the A-LPS antibody was used. Mass spectrometry analysis also demonstrated that the signals corresponded to a wide range of virulence factors including A-LPS-modified proteins such as gingipains. Absorption of serum with LPS resulted in a dramatic reduction of immmunoreactivity. We conclude that LPS and A-LPS-modified proteins in OMVs carry immunodominant determinants and eventually elicit P. gingivalis-specific antibodies in mice.
Department of Bacteriology I, National Institute of Infectious Diseases, 1-23-1, Toyama, Shinjuku-ku, Tokyo 162-8640, Japan Department of Gerodontology, Graduate school of Tokyo Medical and Dental University, 1-5-45, Yushima, Bunkyo-ku, Tokyo 113-8549, Japan.
Dongying
D
Bai
Department of Bacteriology I, National Institute of Infectious Diseases, 1-23-1, Toyama, Shinjuku-ku, Tokyo 162-8640, Japan ryoma73@nih.go.jp.
Ryoma
R
Nakao
Chemical Genetics Laboratory, RIKEN, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan.
Akihiro
A
Ito
Department of Gerodontology, Graduate school of Tokyo Medical and Dental University, 1-5-45, Yushima, Bunkyo-ku, Tokyo 113-8549, Japan.
Hiroshi
H
Uematsu
Department of Bacteriology I, National Institute of Infectious Diseases, 1-23-1, Toyama, Shinjuku-ku, Tokyo 162-8640, Japan.
Hidenobu
H
Senpuku
D000281:Administration, Intranasal; D000818:Animals; D000907:Antibodies, Bacterial / Q000276:immunology*; D000942:Antigens, Bacterial / Q000097:blood / Q000276:immunology*; D001428:Bacterial Vaccines / Q000008:administration & dosage* / Q000276:immunology*; D015153:Blotting, Western; D055252:Cell-Derived Microparticles / Q000276:immunology*; D015180:Electrophoresis, Gel, Two-Dimensional; D005260:Female; D006863:Hydrogen-Ion Concentration; D013058:Mass Spectrometry; D051379:Mice; D008807:Mice, Inbred BALB C; D016966:Porphyromonas gingivalis / Q000276:immunology*; D020543:Proteome / Q000032:analysis; D037521:Virulence Factors / Q000032:analysis / Q000276:immunology
D000907:Antibodies, Bacterial; D000942:Antigens, Bacterial; D001428:Bacterial Vaccines; D020543:Proteome; D037521:Virulence Factors
Porphyromonas gingivalis; intranasal immunization; outer membrane vesicles; periodontitis; vaccine