Fractionation studies on human leucocyte dialyzates. Demonstration of three components with transfer factor activity.

Fractionation of dialyzates of human leucocyte lysates on a Sephadex G-10 column yielded seven fractions. Oidiomycin sensitivity could be induced with fractions I, III and VI in those recipients whose skin tests had previously been negative. Uraemic patients, who were skin test negative to 100 TU of PPD, regained their in vivo reactivity to PPD after receiving 5 mug of fraction VI, while no alteration in their blast transformation responses to the antigen was observed. We suggest that the active components at least in fractions III and VI, and perhaps also in fraction I, act nonspecifically by stimulating weak immune reactivity or by supporting reactions leading to the expression of this reactivity.