ISOLATION AND CHARACTERIZATION OF AN INTERLEUKIN-8-LIKE PEPTIDE IN THE BOVINE SPECIES

Human interleukin-8 (IL-8) is a biologically active peptide which displays chemo-attractive activity for neutrophils and T-cells. The molecule is produced by a variety of cell types upon exposure to lipopolysaccharide, interleukin-l and tumor necrosis factor. Recombinant human IL-8 also stimulates chemotaxis of bovine cells in a dose dependent manner. The purpose of this series of studies was to investigate the ability of bovine cells to produce an active IL-8-like molecule and to determine if bovine cells respond to human recombinant IL-8. Stimulation of purified peripheral blood mononuclear cells results in the time dependent production of an IL-8-like molecule as determined using an anti-human IL-8 ELISA assay and a bovine neutrophil chemotactic assay. Physical characterization indicates that the biological activity of the molecule was significantly reduced by heat inactivation at 56 degrees C for 30 min or exposure to extreme acidic or basic conditions. The peptide was affinity purified using an anti-human IL-8 antibody produced from ATCC hybridoma HB9647. SDS-PACE analysis yields a distinct band at 7.8 kDa. The isoelectric point of the purified protein was determined to be 8.65. Biological activity of the purified protein was confirmed and the anti-human IL-8 antibody was capable of partially neutralizing the chemotactic activity.