Abstract

There is considerable evidence that hearing and vestibular function can be influenced by immune processes. The inner ear has evolved mechanisms, such as the blood-labyrinthine barrier that limit immune responses and autoimmune processes to reduce the potential for damage to cochlear cells. Recently, expression of Fas ligand (FasL) in some non-lymphoid tissue, as in the anterior chamber of the eye, has been hypothesized to play a role in protection of sensitive organs from activated T-cells. We show that under resting conditions, cochlear cells express little or no FasL. However, after exposure to interferon-gamma in vitro, FasL is induced in many neonatal cochlear cells. In addition, we show that FasL is upregulated in adult cochlear cells after induction of a sterile labyrinthitis in vivo. The induction of FasL by inflammation may serve to limit cochlear immune responses, and to protect sensorineural tissue from immune and autoimmune damage.