Human transfer factor: fractionation and biologic activity.

Human transfer factor (TF) was fractionated by exclusion chromatography and the fractions were tested for biologic activity in vivo and in vitro. Specific TF activity in vivo was found to reside in the major UV-absorbing peak (Fraction III). Fraction III eluted at 2.7 X V(O) and transferred tuberculin, candida, or KLH-reactivity to previously negative recipients. Fraction III from nonreactive donors was ineffective. When the fractions were tested in vitro, we found that both the mitogenic activity of whole TF and the suppressive activity to mitogen activation when present in TF was found in Fraction I. Fraction III contained components responsible for augmentation of PHA and PWM responses. In addition, Fraction III contained the component responsible for antigen-dependent augmentation of lymphocyte transformation. Fraction IV was suppressive to antigen-induced lymphocyte transformation. These data suggest that TF preparations contain components which can affect immune reactions in both specific and nonspecific ways.