EFFECT OF HA-1A MONOCLONAL IGM ANTIBODY ON ENDOTOXIN-INDUCED PROLIFERATION OF CULTURED RAT MIDDLE-EAR EPITHELIUM

The effect of human monoclonal antibody HA-1A (Centoxin) on the effect of endotoxin on cultured rat middle ear epithelium was investigated. The addition of endotoxin to the standard culture medium revealed a co ncentration-related proliferative effect on cultured rat middle ear ep ithelium, leading to cobblestone cells, cell tracks, and stratificatio n of epithelium, whereas rat middle ear epithelium cultured in standar d medium grew as a monolayer composed of flat polygonal cells. Additio n of HA-1A to standard medium supplemented with endotoxin gave rise to a statistically significant suppression of the proliferative effects of endotoxin on these cells. The morphology of rat middle ear epitheli um cultured in the presence of HA-1A and endotoxin showed that these c ells still had a tendency to form cobblestone-like cells and cell crac ks, but to a substantially lower degree. The present results support t he hypothesis that HA-1A suppresses the proliferative and morphologica l effects of endotoxin on rat middle ear epithelium and may play an im portant role in the pathogenesis of otitis media.