CHARACTERIZATION OF GLYCOPROTEINS FROM CHLAMYDIA-TRACHOMATIS USING LECTINS

Glycoproteins in Chlamydia trachomatis, serotype L1, elementary bodies were studied by lectin blotting. A panel of 23 lectins representing a variety of sugar specificities was used. The pattern of lectin-bindin g specificities at a peptide band was studied in order to determine th e type and structure of its glycoconjugate. To establish chlamydial or igin of the glycopeptide bands in the blot, control samples from non-i nfected host cell membranes were run in parallel. Terminal mannosidic structures were demonstrated in a 72 kDa glycopeptide (gp72) by its se lective binding of Galanthus nivalis lectin (GNA). Sialic acids were f ound in two chlamydial glycopeptides, gp40 and gp64, which appear to c arry O-linked glycoconjugates as they bound the peanut agglutinin (PNA , both gp40 and gp64) and jackfruit lectin (Jac, only gp40). Such stru ctures were also present in other chlamydial glycopeptides. Lectins wi th specificities for fucose in different links, galactose and N-acetyl glucosamine bound to several chlamydial peptides. On the basis of our results we suggest an alternative mechanism for uptake of chlamydial elementary bodies into host cells, namely phagocytosis mediated by euk aryotic cell surface lectins.