One-way stimulation in mixed leukocyte cultures.

We have developed an improved method for the mixed leukocyte culture test. Control values, as determined by rates of incorporation of thymidine, are very low, allowing evaluation of low levels of stimulation in homologous cell mixtures. One-way stimulation is assayed by treating the cells of one individual with mitomycin C; treated cells cannot respond (incorporate thymidine) but can still stimulate homologous untreated cells to do so.