The murine
S-100 protein designated
CP-10 is a potent
chemotactic factor for phagocytic cells, exhibiting optimal activity in the picomolar range. We assessed the role of this
cytokine in the inflammatory response to
pulmonary injury following intratracheal administration of
bleomycin to mice. In the lungs of normal animals, strong cytoplasmic immunostaining for
CP-10 was demonstrable in all recognisable neutrophil leucocytes 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 neutrophils did not exhibit staining for
CP-10. No other cells were immunoreactive. The concentration of
CP-10 in bronchoalveolar lavage (BAL) fluids from normal mice and mice administered intratracheal saline was below the level of detection by
enzyme immunoassay. In contrast, nanomolar levels of
CP-10 were detected in unconcentrated BAL fluids from C57BL/6 mice after
bleomycin-induced injury, and the presence of monomeric
CP-10 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 resistant to
pulmonary injury by
bleomycin. We conclude that
CP-10 may contribute to the recruitment of inflammatory cells
in bleomycin-induced lung damage.