Characteristics of B-lymphocyte colony growth in vitro.

A cloning system in semisolid agar has been developed which supports colony formation by mouse B-lymphocytes. Colonies appear to be clones and colony cells synthesize immunoglobulin. Approximately one cell in 50 in the spleen or lymph nodes is capable of forming a colony and colony-forming cells appear to have the properties of B-lymphocytes. Colony formation is dependent on mercaptoethanol but the possible additional involvement of a specific B-lymphocyte regulatory factor has not been excluded.