A bioassay for bovine interleukin-1 by the A375 cell growth inhibition

Usefulness of a human melanoma cell line A375 was evaluated for detecting bovine interleukin-1 (IL-1). The A375 cell growth was inhibited by culture supernatant of lipopolysaccharide-stimulated bovine peripheral blood mononuclear cells (LPSsup) in a dose dependent manner. A mixture of anti-human IL-1 alpha and beta antibodies suppressed 60% of this inhibitory activity and was confirmed to bind to about 23 k dalton peptides in the LPSsup by Western blotting. Although serum and bronchoalveolar lavage fluid from a healthy cow showed a low inhibitory activity, those from pneumonic cows showed the higher activities. These activities were also suppressed by anti-human IL-1 antibodies. These findings show the A375 cell growth inhibition assay can be a useful bioassay for bovine IL-1 (like) activity.