SPECIFIC BINDING OF STREPTOCOCCUS-PNEUMONIAE TO 2 RECEPTOR SACCHARIDESTRUCTURES

Specific binding of Streptococcus pneumoniae to two proposed receptor structures was studied in a solid-phase assay. The assay was based on immunodetection of the pneumococci adhering to the receptors coated to microtiter plates. Non-specific binding owing to hydrophobic forces t o uncoated wells could be abolished by treatment of the plates with a blocking buffer. Binding of the pneumococcal cells was demonstrated wi th the glycolipid asialo-GM1 as receptor with a previously suggested s pecificity for the disaccharide GalNAc beta 1-4Gal. A non-capsulated m utant bound with high efficiency to this receptor. Two capsulated stra ins also bound well, but with lower efficiency. Binding of the non-cap sulated strain was also demonstrated with lactotriaosylceramide as rec eptor with a suggested specificity for the disaccharide GlcNAc beta 1- 3Gal. The binding assay enables the comparison of the adherence of dif ferent strains to purified receptor molecules.