Expression Purification And Characterization Of Therapeutic Anti_Cd20 Antibody

Abstract

Monoclonal antibodies are proteins and constitute an important class of therapeutic biologic drugs and are being increasingly used for the past two decades to treat unmet disease conditions such as cancers and auto-immune diseases. Monoclonal antibodies work through mainly three different mechanisms of action such as complement mediated cell cytotoxicity (CDC), apoptosis and antibody dependent cell cytotoxicity (ADCC). Lymphoma, a group of related tumours such as Hodgkin s lymphoma (HL) and Non-Hodgkin s lymphomas (NHL) develop in certain type of cancers. Non-Hodgkin s lymphomas belong to B cell lymphoma category and are the most common and contribute to about 80% of all lymphomas. In NHL tumours, CD20 receptor is overexpressed in B cell lymphomas and hence CD20 receptor becomes a specific target for the therapeutic monoclonal antibodies.One of the current treatment options for B cell lymphomas is chemical cytotoxic agents with immunotherapy. Anti-CD20 monoclonal antibodies are increasingly used for immunotherapy. One of the main mechanisms of action of anti-CD20 antibody is ADCC. At present, several new generation anti-CD20 antibodies are being engineered and/or modified by amino acid sequence changes and glyco-engineering methods to improve anti-tumour activity over currently available anti-CD20 antibodies. In this work, the objective was to improve ADCC activity of anti-CD20 monoclonal antibody through protein expression studies in mammalian cell line with enhanced ADCC activity. Chinese hamster ovary cell line expressing anti-CD20 antibody was generated using recombinant DNA technology. The antibody was purified by using chromatography techniques and characterized using bio-physical and biological assays. For enhancing ADCC activity cell culture conditions such as osmolality and nutrient composition were optimized. Purification process was developed to purify expressed anti-CD20 antibody to desired purity level to render useful for human therapeutic application.