In vitro assay for responsiveness of lymphocytes to transfer factor by a new leukocyte migration inhibitory test.

Transfer factor (TF) causes nonimmune lymphocytes to produce leukocyte migration inhibitory factor (LMIF) in the presence of purified protein derivative (PPD). The activity of TF was measured by leukocyte migration inhibitory test (LMIT). The LMIT was a modification of the conventional agarose droplet method. To express the activity of LMIF quantitatively and simply, LMIF titer was introduced. The LMIF titer was obtained from the combination of two factors, LMIF dilution and cell migration diameter, and therefore this made the LMIT much more sensitive as compared to the conventional LMIT. The responsiveness of lymphocytes from acute lymphoblastic leukemia (ALL) and from cell-mediated immunodeficiency in children to TF was assayed by LMIT. In ALL, the lymphocyte responsiveness was poor in relapse but improved with remission. The responsiveness was remarkably well in 3 patients with cell-mediated immunodeficiency. This method appears useful for the in vitro evaluation of responsiveness of lymphocytes to TF.