Cytoplasmic localization of phytohaemagglutinin in peripheral white cells.

Abstract

SALINE extract of the red kidney bean (Phaseolus vulgaris) possesses a factor which increases the rate of cell division in cultures of peripheral white cells1, and a factor which agglutinates red cells2. Reciprocal absorption shows that the two factors are separate and the mitogenic moiety has been further characterized as a mixture of proteins, the predominant one having a molecular weight of about 128,000 (ref. 3). The mitogenic extract therefore lends itself to labelling with fluorescent compounds. Such a marker would be valuable in tracing the mode of action of the mitogen(s) since it is still not known whether the leucocyte agglutination, apparently inseparable from the mitogenic activity4, is also necessary to the mitogenic activity, nor whether the substance acts extra- or intra-cellularly, or both.