Comparison of Mitomycin C and X-irradiation as Blocking Agents in One-way Mixed Leucocyte Cultures

Abstract

THE mixed leucocyte culture (MLC) test^1,2 has been widely used as a measure of histocompatibility in man and as a model for the recognition phase of the homograft response in vitro. Two methods have been proposed to achieve unidirectional stimulation in MLC: treatment of stimulating cells with either mitomycin C³ or X-irradiation³. The mitomycin C method has the advantage of not requiring expensive X-ray equipment and being immediately available in the laboratory; the X-ray method has the advantage of not requiring washing of the cells following treatment. Although much of the quantitative MLC work for histocompatibility testing in man has been done using mitomycin C, the general impression gained from the literature as well as the studies we report here would support the use of either method. A previous study⁴ suggested that irradiation is superior to mitomycin C treatment for a number of reasons, but we question those conclusions.