Colony formation by normal and malignant human B-lymphocytes

A method is described that permits colony formation in culture by B lymphocytes from normal blood and from blood, marrow or lymph nodes of patients with myeloma or lymphoma. The method depends on: (1) exhaustively depleting cell suspensions of T lymphocytes, (2) a medium conditioned by T lymphocytes in the presence of phytohaemagglutinin (PHA-TCM), and (3) irradiated autologous or homologous T lymphocytes. Under these conditions the assay is linear. Cellular development of B lymphocytes can be followed; differentiation to plasma cells is seen in cultures of cells from normal individuals and myeloma patients, but not lymphoma patients. Malignant B lymphocytes in culture produced immunoglobulin of the class identified in the patient's blood, or in freshly obtained cells. We conclude that the assay is suitable for studying the growth, differentiation and regulation of normal and malignant B lymphocytes in culture.