Recombinant bovine interferon-alpha I 1 inhibits the migration of lymphocytes from lymph nodes but not into lymph nodes.

Recombinant bovine interferon-alpha I 1 (IFN-alpha) was tested for effects on lymphocyte migration into and out of the lymph nodes of sheep. Chronic lymph drainage methods were used to monitor the efferent lymph of single lymph nodes of unanaesthetized animals. When IFN-alpha was injected into the drainage area of the lymph node, infused directly via an afferent lymphatic, or injected intravenously, a marked decrease in cell output was observed. Nanogram quantities of IFN-alpha produced an effect that lasted several hours. To test whether this effect was specific for lymphocytes, we first stimulated a lymph node with Staphylococcus aureus so that large numbers of neutrophils and lymphocytes were present in efferent lymph. When IFN-alpha was then injected, the lymphocytes disappeared from efferent lymph but the neutrophils did not. Normal efferent lymph cells were labeled with radioisotopes and injected intravenously during the IFN-alpha induced effect. The entry of lymphocytes from the blood was significantly enhanced at a time coinciding with the suppressed cell exit in the efferent lymph. Recovery data indicated that the lymphocytes were retained temporarily in the lymph node but were not destroyed. Furthermore, the bovine IFN-alpha does not appear to be conspicuously antigenic in sheep. It is not yet certain whether IFN-alpha enhances the interactions of cells within the lymph node thereby potentiating immunologic reactions.