title: Characterization of human-type monoclonal antibodies against reduced form of hemin binding protein 35 from Porphyromonas gingivalis.
abstract: OBJECTIVE
  The gram-negative anaerobe Porphyromonas gingivalis has been implicated as an important pathogen in the development of adult periodontitis, and its colonization of subgingival sites is critical in the pathogenic process. We previously identified a 35 kDa surface protein (hemin binding protein 35; HBP35) from P. gingivalis that exhibited coaggregation activity, while additional analysis suggested that this protein possessed an ability to bind heme molecules. For development of passive immunotherapy for periodontal diseases, human-type monoclonal antibodies have been prepared using HBP35 as an antigen in TransChromo mice. In the present study, we focused on a single antibody, TCmAb-h13, which is known to inhibit heme binding to recombinant HBP35. The aim of our investigation was to clarify the redox-related function of HBP35 and consider the benefits of human-type monoclonal antibodies.
  
  
  METHODS
  To examine the antigen recognition capability of TCmAbs with immunoblotting and Biacore techniques, we used the native form as well as several Cys-to-Ser variants of recombinant HBP35.
  
  
  RESULTS
  We found that the redox state of recombinant HBP35 was dependent on two Cys residues, (48) C and (51) C, in the thioredoxin active center (WCGxCx). Furthermore, TCmAb-h13 recognized the reduced forms of recombinant HBP35, indicating its inhibitory effect on P. gingivalis growth.
  
  
  CONCLUSIONS
  Hemin binding protein 35 appears to be an important molecule involved in recognition of the redox state of environmental conditions. In addition, TCmAb-h13 had an inhibitory effect on heme binding to recombinant HBP35, thereby interfering with P. gingivalis growth.
authors.affiliation: Department of Biochemistry and Molecular Biology, Nihon University School of Dentistry at Matsudo, Chiba, Japan.
authors.forename: Y
authors.initials: Y
authors.lastname: Shibata
authors.forename: S
authors.initials: S
authors.lastname: Okano
authors.forename: T
authors.initials: T
authors.lastname: Shiroza
authors.forename: T
authors.initials: T
authors.lastname: Tahara
authors.forename: K
authors.initials: K
authors.lastname: Nakazawa
authors.forename: S
authors.initials: S
authors.lastname: Kataoka
authors.forename: I
authors.initials: I
authors.lastname: Ishida
authors.forename: T
authors.initials: T
authors.lastname: Kobayashi
authors.forename: H
authors.initials: H
authors.lastname: Yoshie
authors.forename: Y
authors.initials: Y
authors.lastname: Abiko
mesh_terms: D019943:Amino Acid Substitution; D000818:Animals; D061067:Antibodies, Monoclonal, Humanized / Q000737:chemistry / Q000276:immunology*; D001426:Bacterial Proteins / Q000276:immunology*; D002352:Carrier Proteins / Q000737:chemistry / Q000276:immunology*; D003545:Cysteine; D000081062:Heme-Binding Proteins; D006420:Hemeproteins / Q000737:chemistry / Q000276:immunology*; D006427:Hemin / Q000378:metabolism; D006801:Humans; D007116:Immunization, Passive / Q000379:methods*; D051379:Mice; D008822:Mice, Transgenic; D016966:Porphyromonas gingivalis / Q000737:chemistry / Q000254:growth & development* / Q000276:immunology; D011485:Protein Binding / Q000276:immunology; D017434:Protein Structure, Tertiary; D012694:Serine; D013879:Thioredoxins / Q000737:chemistry; D037521:Virulence Factors / Q000276:immunology
chemical_list: D061067:Antibodies, Monoclonal, Humanized; D001426:Bacterial Proteins; D002352:Carrier Proteins; D000081062:Heme-Binding Proteins; D006420:Hemeproteins; D037521:Virulence Factors; D012694:Serine; D013879:Thioredoxins; D006427:Hemin; D003545:Cysteine