In vitro transfer of specific reactivity to cytomegalovirus and candida to cord blood leukocytes with dialyzable leukocyte extracts

The ability of two preparations of dialyzable leukocyte extracts (DLE, formerly termed “dialyzable transfer factor”) to induce specific responsiveness by cord blood leukocytes (CBL) in the direct leukocyte migration inhibition (LMI) assay in vitro was studied. One donor of DLE (DLE-A) was immune to cytomegalovirus (CMV), as judged by positive LMI test, and negative to candida as judged by skin test. The other donor (DLE-B) was immune to both CMV and candida. Several concentrations of DLE and of antigen were tested. High concentrations of DLE nonspecifically inhibited leukocyte migration, while low concentrations had no effect on antigen-induced LMI. Antigen-specific conversion was produced by intermediate concentrations of DLE. Both preparations transferred reactivity to CMV, but only DLE-B transferred reactivity to candida in vitro.