Studies of murine lymphocyte alloantigens Ly-7.2.

The Ly-7.2 alloantigen has previously been defined by an alloantiserum and shown to be expressed on T and B cells; it is now studied for its distribution on responder and stimulator cells in the mixed lymphocyte reaction, on cells responding to mitogens and on mitogen-induced blast cells. In the mixed lymphocyte reaction, the responder cells were Ly-7.2+; stimulator cells were Ly-7.2-. The Ly-7.2 antigen also had an unusual distribution on cells responding to mitogens: leucoagglutinin-responsive cells were Ly-7.2-, concanavalin A Ly-7.2+, pokeweed mitogen Ly-7.2+/-, and lipopolysaccharide Ly-7.2-, i.e., Ly-7 can distinguish between subpopulations of T cells which respond to mitogens (phytohaemagglutinin and concanavalin A). Ly-7.2 was present on approximately 60% of blast cells induced by all mitogens indicating that both Ly-7.2+ and Ly-7.2- cells could be activated to become Ly-7.2+. Further characterization of concanavalin A and leucoagglutinin-stimulated Ly-7.2+ and Ly-7.2- T blast cells with anti-Ly-2.1 and anti-Ia. 17 monoclonal antibodies demonstrated the presence of several T lymphocyte subsets as both Ly-7+ and Ly-7- blast cells contained Ly-2+, Ly-2-, Ia+ and Ia- cells. Ly-7.2 therefore has a heterogenous distribution on normal and activated T and B cell subpopulations, and is a potentially important antigenic marker for studies of lymphocyte differentiation and function.