Shared idiotypic determinant in mono- and polyclonal anti-phospholipid antibodies with lupus anticoagulant activity.
Of 42 purified human myeloma proteins tested, two (IgG3 Her and IgM Mag) were found to possess strong lupus anticoagulant (LA) and anti-cephalin activity, as assessed by a dilute activated partial thromboplastin time (dAPTT) and ELISA test, respectively. For these proteins, we confirmed the observation reported by others that LA activity is present in the antigen-binding (Fab) portion of the immunoglobulin molecule. Rabbit anti-idiotype antibodies against IgG3 Her inhibited the anti-cephalin activity of this protein, suggesting that the anti-cephalin activity of IgG3 Her depends on the hypervariable part of the immunoglobulin and thus most probably is a true antigen-antibody reaction. The anti-Her idiotype antibodies were also able to bind to and inhibit the anti-cephalin activity of IgM Mag. ELISA binding and inhibition experiments showed that the anti-idiotype antiserum contained at least two sets of anti-idiotypes; one set that recognizes a cross-reactive idiotype shared by IgG3 Her and IgM Mag, and another set that seems to be unique to the immunizing protein IgG3 Her. Both sets of anti-idiotype antibodies also bound weakly to polyclonal (patient) IgG, indicating an idiotypic cross reaction.
Wisløff
F
F
Haematological Research Laboratory, Ullevål Hospital, University of Oslo, Norway.
Sletnes
K E
KE
Michaelsen
T
T
D000888:Antibodies, Anti-Idiotypic / Q000032:analysis* / Q000276:immunology; D000911:Antibodies, Monoclonal / Q000276:immunology*; D001777:Blood Coagulation / Q000276:immunology*; D001779:Blood Coagulation Factors / Q000032:analysis / Q000276:immunology*; D004797:Enzyme-Linked Immunosorbent Assay; D006801:Humans; D007140:Immunoglobulin Fab Fragments / Q000032:analysis / Q000276:immunology; D007141:Immunoglobulin Fc Fragments / Q000032:analysis / Q000276:immunology; D007128:Immunoglobulin Fragments / Q000032:analysis / Q000276:immunology; D007074:Immunoglobulin G / Q000032:analysis* / Q000276:immunology; D007075:Immunoglobulin M / Q000032:analysis / Q000276:immunology; D016682:Lupus Coagulation Inhibitor; D010314:Partial Thromboplastin Time; D010714:Phosphatidylethanolamines / Q000276:immunology*
D000888:Antibodies, Anti-Idiotypic; D000911:Antibodies, Monoclonal; D001779:Blood Coagulation Factors; D007140:Immunoglobulin Fab Fragments; D007141:Immunoglobulin Fc Fragments; D007128:Immunoglobulin Fragments; D007074:Immunoglobulin G; D007075:Immunoglobulin M; D016682:Lupus Coagulation Inhibitor; D010714:Phosphatidylethanolamines