BOVINE ENA, A NEW MONOCYTE-MACROPHAGE DERIVED CYTOKINE OF THE INTERLEUKIN-8 FAMILY - STRUCTURE, FUNCTION, AND EXPRESSION IN ACUTE PULMONARYINFLAMMATION

A novel bovine neutrophil-activating peptide, bovine ENA (boENA), was identified ill the conditioned media of endotoxin-stimulated bovine mo nocytes and alveolar macrophages. The chemotactic peptide was purified to homogeneity from conditioned media by cation-exchange chromatograp hy and several steps of reversed-phase high-performance liquid chromat ography. The partial amino acid sequence of boENA was: VVRELRCVCLTTTPG IHPKTVSDLQVIAAGPVCSKVEVIATLKNGXXV. Its cysteine molecules are position ed identically to those of the C-X-C family of human proinflammatory p eptides. BoENA shows structural (73% identity in amino acid sequence) and functional homology to human ENA-78, a product of the human type I I epithelial cell line A549, as demonstrated in assays for chemotaxis, aggregation, shape change, and a rise ill intracellular free calcium. The immunohistochemical identification of boENA in the hyperplastic t ype II alveolar epithelial cells and in pulmonary alveolar leukocytes of pneumonic bovine lungs strongly supports a role for ENA-78 in the g enesis of pulmonary inflammation.