title: Epitope analysis of human immunoglobulin D with a mouse monoclonal anti-Fab delta chain antibody.
abstract: BACKGROUND
  The clinical significance of IgD measurements in serum is limited as the frequency of abnormal concentrations is rare.
  
  
  METHODS
  We prepared a mouse monoclonal antibody and a rabbit polyclonal antibody against Fab delta and Fc delta chain and compared epitope recognition by the monoclonal antibody against Fab delta (anti-Fab delta mono) with that by other antibodies.
  
  
  RESULTS
  Anti-Fab delta mono specifically reacted with purified IgD and Fab delta of myelomatous origin, but not with other isotypes and light chains. In 19 of 22 myeloma sera, the monoclonal antibody recognized intact IgD and/or its fragments when analyzed by immunoblotting. Of these there were only four cases in which possible Fab delta fragments were identified. The other three sera showed no reactivity with the antibody and the IgD value was low on a chemiluminescence enzyme immunoassay.
  
  
  CONCLUSIONS
  These findings indicate the presence of at least two immunochemically different IgD molecules in the sera. No positive reaction with any synthetic peptide was observed for the antibody on delta-chain ranging from N-terminus of JH, C delta 1 to a hinge region. We suggest that the epitope recognized by the antibody is related to the variable region or a conformational structure on the Fd delta region of IgD.
authors.affiliation: Biochemical Research Laboratory, Research and Development Headquarters, Eiken Chemical Co., Ltd., 143 Nogi, Nogi-machi, Shimotsuga-gun, Tochigi-ken, 329-0114, Japan. massaaki_arakawa@eiken.co.jp
authors.forename: Masaaki
authors.initials: M
authors.lastname: Arakawa
authors.forename: Yoshihisa
authors.initials: Y
authors.lastname: Itoh
authors.forename: Naofumi
authors.initials: N
authors.lastname: Yoshioka
authors.forename: Ikunosuke
authors.initials: I
authors.lastname: Sakurabayashi
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D000911:Antibodies, Monoclonal / Q000737:chemistry / Q000276:immunology*; D000918:Antibody Specificity; D004591:Electrophoresis, Polyacrylamide Gel; D000939:Epitopes / Q000737:chemistry / Q000276:immunology*; D006801:Humans; D007124:Immunoenzyme Techniques; D007072:Immunoglobulin D / Q000097:blood* / Q000737:chemistry / Q000276:immunology*; D007140:Immunoglobulin Fab Fragments / Q000737:chemistry / Q000276:immunology*; D007138:Immunoglobulin delta-Chains / Q000276:immunology*; D051379:Mice; D011817:Rabbits
chemical_list: D000911:Antibodies, Monoclonal; D000939:Epitopes; D007072:Immunoglobulin D; D007140:Immunoglobulin Fab Fragments; D007138:Immunoglobulin delta-Chains