Cytotoxic properties of the eosinophil major basic protein.

Summary The eosinophil major basic protein (MBP) damages cells including those from organs whose dysfunction is associated with eosinophil infiltration. Concentrations of MBP in the toxic range were found in sputa from asthmatics, in pleural fluid and in sera. These findings suggest the hypothesis that the eosinophil produces damage to cells in disease.