Lysozyme activity and distribution in lesions.

(A) Lysozyme concentration 48 hours after M luteus injection in tissues of lys M^−/− mice (○; n = 4) compared with F2 control mice (●; n = 3). The difference between the geometric means, 4.79 μg/mL vs 72.4 μg/mL, is significant atP = .004 (t test, after logarithmic transformation). (B-C) Sections of lesions from an F2 control and lys M^−/− mouse, respectively, immunostained with antibody reactive with lysozymes M and P (red stain, blue hematoxylin nuclear counterstain). Note that most inflammatory cells in the lesions of F2 mice are reactive with antilysozyme antibody, but in lys M^−/− lesions inflammatory cells with polymorphonuclear morphology (neutrophils) are not reactive. (D-E) Lesions of F2 mice show only background fluorescence, while those of lys M^−/− mice express abundant EGFP from the knockout construct.