Antifluorescein affinity columns: Isolation and immunocompetence of lymphocytes that bind fluoresceinated antigens in vivo or in vitro*

A new method for the isolation of specific immunocompetent lymphocytes has been described in which lymphocyte populations are exposed to fiuoresceinated antigens (FLAGs) in vivo or in vitro, and the FLAG-binding cells retained on antifluorescein affinity columns. Specific cells are then eluted with an unrelated FL-labeled protein and shown to be fully immunocompetent. This methodology has been applied successfully in diverse antigenic systems including polymerized flagellin and TNP-specific B cells and alloantigen-reactive cytotexic T lymphocytes. The method is rapid, inexpensive (requiring only antifluorescein beads), and can be applied to any antigens (or antibodies) in which a fluorescein group can be introduced.