Résumé
Differences in activity among the family of human IFNs α are much reduced if these ligands are assayed on bovine cells. In particular, the activity of IFN αD is much higher on bovine than on human cells. To examine these differences, the bovine counterpart of the human IFNAR has been cloned and expressed in a human cell line. The transfected cell line now recognizes the human IFN αD as a high-specific-activity IFN subtype, indicating that the differences in sensitivity between the bovine and human cells to the human IFN α lie in the structure of the IFNAR chain rather than in the other components of the functional receptor.