IMMUNODETECTION OF THE MURINE CHEMOTACTIC PROTEIN CP-10 IN BLEOMYCIN-INDUCED PULMONARY INJURY

The murine S-100 protein designated CP-10 is a potent chemotactic fact or for phagocytic cells, exhibiting optimal activity in the picomolar range. We assessed the role of this cytokine in the inflammatory respo nse to pulmonary injury following intratracheal administration of bleo mycin to mice. In the lungs of normal animals, strong cytoplasmic immu nostaining for CP-10 was demonstrable in all recognisable neutrophil l eucocytes sequestered within alveolar capillaries. Following induction of pulmonary inflammation in susceptible C57BL/6 mice, numerous CP-10 -positive neutrophils were observed, but many of the recruited neutrop hils did not exhibit staining for CP-10, No other cells were immunorea ctive. The concentration of CP-IO in bronchoalveolar ravage (BAL) flui ds from normal mice and mice administered intratracheal saline was bel ow the level of detection by enzyme immunoassay. In contrast, nanomola r levels of CP-10 were detected in unconcentrated BAL fluids from C57B L/6 mice after bleomycin-induced injury, and the presence of monomeric CP-IO was demonstrable by Western blotting. Elevation of CP-10 levels correlated with the influx of inflammatory cells in C57BL/6 mice, but was not demonstrable in BAL fluids from BALB/c mice, which are resist ant to pulmonary injury by bleomycin, We conclude that CP-10 may contr ibute to the recruitment of inflammatory cells in bleomycin-induced lu ng damage.