Analysis of immunocompetent cells following inner ear immunostimulation

Immunohistochemical methods were used to investigate the development of inner ear immunocompetent cells in healthy, BALB/c mice over a 3-week period as a result of a secondary inner ear response against keyhole limpet hemocyanin. Antibodies against murine macrophages and granulocytes (anti-Mac-1), T-cells (anti-Lyt-1, anti-Lyt-2), and immunoglobulins (anti-IgM, anti-IgG, anti-IgA) were used. Mac-1 positive (Mac-1+) cells were observed at 6 hours post-challenge in the endolymphatic sac and cochlea and rapidly increased in both sites. Lyt-1+ cells gradually increased in the endolymphatic sac after challenge, peaking at 2 and 3 weeks post-challenge. In the cochlea, Lyt-1+ cells were detected at 1 day post-challenge and then increased. Lyt-2+ cells were detectable in the endolymphatic sac and the cochlea by 3 weeks post-challenge. The predominant immunoglobulin-bearing cell in the endolymphatic sac was IgG, followed by IgM, with IgA seen late in the response. We conclude that the inner ear has the capacity to mount an immune response through the accumulation of the needed immunocompetent cells for antigen processing, antibody production, and modulation of the response through T-helper and suppressor cell activity.