Effects of dialyzable leukocyte extracts with transfer factor activity on leukocyte migration in vitro. 1. Antigen-dependent inhibition and antigen-independent inhibition and enhancement of migration.

The effects of DLE containing TFd activity from immune human donors on PBL, obtained from individuals nonresponsive to either PPD or Cocci antigen, were evaluated in vitro by the agarose LMl technique. Several different preparations of DLE were employed to evaluate the specificity and reproducibility of the effects: (1) from donors skin test positive to PPD but negative to Cocci, (2) from donors skin test negative to PPD but positive to Cocci, (3) from donors skin test positive to both antigens, and (4) from donors skin test negative to both antigens. With PBL from other human donors used as target cells in the direct agarose LMi technique, three types of effects were demonstrated for all preparations of DLE: (1) antigen-dependent specific LMl, (2) antigen-independent or nonspecific LMl, and (3) antigen-independent enhancement of migration. The demonstration of each activity was found to depend on the concentration of DLE used and the time allowed for migration. In experiments employing purified PMN and MNL as target cells and a two-step indirect LMl assay, it was shown that the antigen-independent effects resulted from the direct of components in DLE on PMN. The antigen-independent inhibition was shown not to result from toxic effects of DLE. It was produced by DLE but not by dialyzable liver or skin extracts when tested using an amount equivalent to DLE as judged by the absorbance at 260 and 280 nm. The antigen-dependent LMl was found to require secretion of a soluble mediator of molecular weight near 69,000, believed to be LMl. Our results indicate that the agarose LMl technique is a useful in vitro assay for studies of the mechanism of action of components in DLE which can specifically convert nonimmune lymphocytes to a measurable antigen-sensitive state (i.e., transfer factor). The antigen-independent effects of DLE may be responsible in part for previously reported nonspecific beneficial effects of DLE when used in immunotherapy.