Production of non-pathogenic human monoclonal antibodies to desmoglein 3 from pemphigus vulgaris patient.

Pemphigus vulgaris is a potentially fatal autoimmune mucocutaneous disease associated with production of IgG autoantibodies to desmoglein 3, a 130 kDa epidermal protein. To further characterize the epitope(s) of pemphigus vulgaris antigen we established two human-human hybridoma by fusion of the peripheral blood mononuclear cells with a human and mouse heterohybridoma. These hybridomas designated as MAb Dsg-3: 06 and MAb Dsg-3: 10 and stable in culture and demonstrated yield of monoclonal antibodies specific for pemphigus vulgaris. Immunofluorescence, immunoblot, ELISA assays demonstrated that both the monoclonal antibodies bind to the intercellular cement substance and to 130 kDa protein present in the skin and specifically binds to recombinant desmoglein 3 protein, but not to desmoglein 1 protein. The IgG subclass distribution study demonstrated that both the antibodies are of IgG1 subclass in nature. Both the antibodies were non-pathogenic as demonstrated in vitro by their inability to produce acantholysis in normal human skin in organ culture or in vivo by the induction of disease in neonatal BALB/c mice. The relevance and value of these monoclonal antibodies in the pathogenesis of pemphigus vulgaris is discussed.