Immunoassays evaluating recombinant IgG binding to Desmin.

<p>Independent immunoassays were used to demonstrate that recombinant immunoglobulin derived from an IBM muscle-associated plasma cell (rIgG-5) binds to human Desmin. (A) Human muscle homogenates were resolved by SDS-PAGE then transferred to membranes that were probed with IBM-derived recombinant rIgG-5 (lane 1) or a commercial anti-Desmin monoclonal antibody (lane 2). (B) Purified human Desmin was resolved by SDS-PAGE then transferred to membranes that were probed with IBM-derived rIgG-5 (lane 1) or rIgG-D3a (lane 2), which was derived from an immature antigen-inexperienced peripheral human B cell. (C) ELISA assays demonstrating IBM-derived immunoglobulin (rIgG-5) binding to the human muscle protein Desmin. ELISA plates were coated with either Desmin (left panel) or Vimentin (right panel) then probed with IBM rIgG-5 and a rIgG (D3a) derived from a single B cell from a normal healthy donor. Monoclonal antibodies (mAb) specific for each antigen were used as positive controls.