Abrin and hurin: two new lymphocyte mitogens.

Two plant proteins, abrin from the seed of Abrus precatorius and hurin from the seed of Hura crepitans, are potent lymphocyte mitogens. The extent of stimulation of BALB/C AND CBA strain mouse spleens by these factors is significantly greater than that attained with PHA or PWM and requires thymus-derived lymphocytes. Abrin has been purified to electrophoretic homogeneity, physically characterized, and may undergo conversion from a toxic to mitogenic form. Hurin is the best mitogen we have tested.