Isolation and purification of HLA-DR antigen from Daudi cell line by immunoaffinity chromatography

Introduction: The major histocompatibility complex (MHC) is a group of cell surface proteins that are essential for recognizing foreign molecules in human and other mammals. The physiologic function of MHC molecules is the presentation of peptides to T cells. In this study, we evaluated the purification of a class II MHC molecule (HLA-DR) from a human Burkitt′s lymphoma cell line; Daudi. Materials and methods: We described a simple procedure for purifying human HLA molecules from the cells lysate. As a representative model, HLA-DR was purified from Daudi cell line. The cell membrane was solubilized by a buffer contained NP-40 detergent. Subsequently, the isolation of the membrane antigen was carried out by affinity chromatography method using mouse anti-human HLA-DR monoclonal antibody. The size and the specificity of the purified antigen were determined by Bradford and ELISA methods, respectively. Results: The purified HLA antigen was obtained in approximately 20-30 micrograms in each run of chromatography. Additionally, ELISA method demonstrated the HLA-DR specificity of the purified protein. Conclusion: The results indicated that affinity purification of HLA-DR antigen by means of specific monoclonal antibody is a simple and fast procedure for obtaining the purified antigen.