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 serotypes 3, 6A and 14 to ciliated chinchilla respiratory epithelium was investigated using a whole organ perfusion technique. We demonstrated that Spn adhere to chinchilla tracheal epithelium within 30 min and exhibit saturation 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 asialoIganglioside GM1 (aGM1), recognized by glycoconjugate analogs of known Spn receptors. NeurIaminidase treatment of the tracheae increased Spn adherence in vitro and reversed the inhibition effect of LNnT suggesting that neuraminidase treatment resulted in an increase in the number of available receptors for Spn. The chinchilla trachea organ perfusion 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.