B220 is widely used in the field of immunology and cell biology as a marker for B cells. It is commonly employed in flow cytometry to identify and isolate B lymphocytes from mixed cell populations. This application is crucial in research focused on understanding immune responses, B cell development, and diseases like leukemia and lymphoma. Additionally, B220 aids in studying the role of B cells in autoimmune disorders and vaccine efficacy, making it a valuable tool in both basic and clinical research.