Antigen Long Description: The original antibody was isolated from a human scFv phage display library by panning against human CD72 receptor using human tonsillar mononuclear cells. The phage library was further enriched using peripheral blood B lymphocytes as target in presence of anti-CD19 antibody. The final round of panning was done against peripheral blood CD19+B cells and subsequently tested for binding to CD72- transfected L929 cells. Later on the scFv antibody was converted to human IgG1 format using antibody engineering.