Immunologic and Electrophysiological Response to Cytomegaloviral Inner Ear Infection in the Guinea Pig

We investigated the development of labyrinthitis in animals inoculated with guinea pig cytomegalovirus (GPCMV). These animals all became deaf eight days after inoculation into the perilymphatic compartment and showed severe inflammatory changes within the inner ear. Animals that received inactivated virus maintained their hearing throughout the observation period and exhibited normal cochlear morphology. Neither group had serum or perilymph antibody to GPCMV eight days after viral inoculation. We then investigated the effect of systemic immunity to GPCMV on inner ear viral challenge in animals with high levels of serum antibodies to GPCMV. No significant hearing loss could be detected eight days after inner ear inoculation. Seropositive animals that received live virus demonstrated a significant rise in perilymph antibody titer to GPCMV and showed preservation of normal cochlear morphology. Thus, systemic and inner ear immunity to GPCMV afforded protection against damage caused after direct perilymphatic inoculation of live virus.