title: B-1 cell-derived monoclonal antibodies and costimulatory molecules.
abstract: BACKGROUND
  B-1 cells represent a specialized subset of B cells that are distinct from conventional B cells. The exact role of B-1 cells is still under investigation. The purpose of this study was to characterize B-1 cell-derived monoclonal antibodies and to examine the expression of costimulatory molecules (MHC class, B7.1 and B7.2) by splenic and peritoneum-derived (PerC) B cells to a different antigenic stimulation.
  
  
  METHODS
  As presentation of antigens to T lymphocytes by B-1 cells is difficult to evaluate at the human level, we used inbred mice. We established hybridoma producing B-1 cell-derived monoclonal antibodies to characterize them to the exogenous and endogenous antigens. Expression of MHC Class, B7.1, and B7.2 by splenic and PerC B cells to a different antigenic stimulation was also evaluated by flow cytometric analysis.
  
  
  RESULTS
  We established two B-1 cell-derived clones demonstrating similarity in their manner of polyreactivity and in terms of their dose-saturable response to the multiple antigens. Splenic and PerC B cells revealed a similar pattern of MHC expression. However, B7.1 and B7.2 were expressed higher in both B cells, while these were more pronounced in PerC B cells.
  
  
  CONCLUSIONS
  B-1 cell-derived monoclonal antibodies were characterized as polyreactive in nature to a panel of exogenous and endogenous antigens. Splenic and PerC B cells revealed a distinctive pattern in their mode of expressing costimulatory molecules when challenged by exogenous or endogenous antigens.
authors.affiliation: Department of Periodontology, School of Dentistry, Pusan National University and Medical Research Institute, Pusan National University, Seo-Ku, Pusan, Korea.
authors.forename: Juyoun
authors.initials: J
authors.lastname: Lee
authors.forename: Joyoung
authors.initials: J
authors.lastname: Suh
authors.forename: Jeomil
authors.initials: J
authors.lastname: Choi
mesh_terms: D019264:Adoptive Transfer; D000818:Animals; D000911:Antibodies, Monoclonal / Q000276:immunology / Q000378:metabolism*; D000941:Antigens / Q000276:immunology / Q000378:metabolism / Q000494:pharmacology; D016175:B-Lymphocyte Subsets / Q000276:immunology* / Q000378:metabolism; D018122:B7-1 Antigen / Q000276:immunology / Q000378:metabolism*; D051940:B7-2 Antigen / Q000276:immunology / Q000378:metabolism*; D005434:Flow Cytometry; D018398:Homeodomain Proteins / Q000235:genetics; D006825:Hybridomas; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D010537:Peritoneum / Q000166:cytology; D013154:Spleen / Q000166:cytology
chemical_list: D000911:Antibodies, Monoclonal; D000941:Antigens; D018122:B7-1 Antigen; D051940:B7-2 Antigen; D018398:Homeodomain Proteins; C064658:RAG-1 protein