Prospective partition analysis of independently assorted sets. Accessory elements supporting clonal lymphoid activation by mitogens.

Accessory cells for mitogen-induced clonal proliferation of lymphocytes can be found after in vitro culture of murine spleen cells. Mitogenic activation of T cells (concanavalin A) depends on such accessory cells. When the cultures in which the accessory cells developed are partitioned, assortment of the accessory cells in cultures is found. When small numbers (1-10) of responder cells, T cells, are dispensed into the above cultures, clonal growth of the T cells is achieved. Neither the dose-response profile of accessory cells nor that of responding cells shows single hit kinetics. Re-categorizing the data set reveals that only cultures with over 20 adherent cells were likely to promote T cell growth and single hit kinetics for the responding cell clone and the accessory cell clone were obtained.