Effect of lacto-N-neotetraose, asialoganglioside-GM1 and neuraminidase on adherence of otitis media-associated serotypes of Streptococcus pneumoniae to chinchilla tracheal epithelium

The adherence of Streptococcus pneumoniae (Spn) otitis media-associated ser otypes 3, 6A and 14 to ciliated chinchilla respiratory epithelium was inves tigated using a whole organ perfusion technique. We demonstrated that Spn a dhere to chinchilla tracheal epithelium within 30 min and exhibit saturatio n kinetics indicating that the effect being observed is receptor mediated. Inhibition of adherence was achieved by prior incubation of Spn with lacto- N-neotetraose (LNnT) or asialo-ganglioside GM1 (aGM1), recognized by glycoc onjugate analogs of known Spn receptors. Neuraminidase treatment of the tra cheae increased Spn adherence in vitro and reversed the inhibition effect o f LNnT suggesting that neuraminidase treatment resulted in an increase in t he number of available receptors for Spn. The chinchilla trachea organ perf usion culture system used in this study imitates eustachian tube conditions more closely than isolated cell culture systems and is a useful model for investigating the role of Spn adherence in vitro in the pathogenesis of OM. (C) 1999 Academic Press.