Structural characterization of skin-directed autoantibodies and their interaction with the antigen to gain insights into autoimmune pre-disease

Structural characterization of proteins, including antibodies and antigens, is invaluable for understanding the relation between structural properties and biological function (and activity), allowing for design of new drug molecules and elucidation of pathophysiological mechanisms. It has been suggested that the NC16A domain of BP180, the immunodominant epitope in bullous pemphigoid, undergoes significant structural/conformational changes when anti-BP180 abs bind, potentially leading to a much better (but detrimental) exposure of the autoantigen towards the adaptive immune system in an early, rather subclinical phase of disease initiation (i.e., autoimmune pre-disease), and potentially activating intracellular signaling cascades. Likewise, little is known about structural changes induced by anti-Dsg3/1 antibodies during binding to their autoantigens Dsg3/1 in pemphigus diseases and its effects on eliciting an aberrant immune response. Importantly, in-silico modeling is not available for most of the above described monoclonal antibodies (and their protein interactions), and new crystallization data are vital for enabling such predictions. We here set out to establish efficient procedures for (i) protein crystallization of monoclonal antibodies directed against skin antigens, (ii) protein crystallization of complexes of antigen and antibody, and (iii) analysis of obtained data. All antibodies and antigens are available in recombinant form.