Figure 4

Depletion of lysozyme M affects the course of middle ear inflammation. The illustration of the mouse tympanic membrane and the otoscopic views show clinical grades (0, 1 and 2) of the middle ear inflammation (A). OS: ossicles. TM: tympanic membrane. *: the epitympanic space with air-fluid level. White arrow heads: middle ear effusions. The otoscopic findings show that the middle ear inflammation is severe at 1 day after inoculation of live S. pneumoniae 6B in lysozyme M^-/- mice, compared to wild type mice (B). However, the later clinical courses are not different between wild type and lysozyme M^-/- mice. This indicates that lysozyme M plays an important role at the early phase of infection, corresponding with the bacterial clearance result (see Table 2). N: number of animals. **: Fisher Exact Test, p < 0.01.