Detection of cross-reactive determinants shared by human monoclonal IgM reacting with myelin-associated glycoprotein.
Monoclonal IgM from patients with peripheral neuropathy frequently have anti-myelin-associated glycoprotein (MAG) activity. We investigated the idiotypes of 10 monoclonal anti-MAG by using rabbit polyclonal antisera. Three groups of anti-idiotypic antisera could be distinguished. Four sera reacted only with the immunizing protein. Two sera reacted with a single other anti-MAG IgM in addition to the immunizing one. Immunoenzymatic studies showed that these two couples of anti-MAG IgM reacted identically with 100% cross-inhibition, indicating that the whole set of idiotypes identified by the rabbit antiserum was present on both IgM antibodies. The four other anti-idiotypic sera reacted with the homologous IgM, as well as with most of the other anti-MAG IgM. In contrast to the previous antisera the binding of these four sera to the homologous IgM could not be inhibited by other cross-reacting anti-MAG IgM. However, when a heterologous IgM was used for coating, these antisera with one exception showed complete cross-inhibition. The absence of inhibition by purified MAG of the patient of the anti-idiotypic antisera sera suggests that these antibodies are most likely to be directed against framework determinants rather than against combining site epitopes.
D000911:Antibodies, Monoclonal / Q000276:immunology*; D003429:Cross Reactions; D004797:Enzyme-Linked Immunosorbent Assay; D000939:Epitopes; D006801:Humans; D007130:Immunoglobulin Idiotypes / Q000276:immunology*; D007075:Immunoglobulin M / Q000276:immunology; D009185:Myelin Proteins / Q000276:immunology*; D018992:Myelin-Associated Glycoprotein
D000911:Antibodies, Monoclonal; D000939:Epitopes; D007130:Immunoglobulin Idiotypes; D007075:Immunoglobulin M; D009185:Myelin Proteins; D018992:Myelin-Associated Glycoprotein