Attachment of gonococcal pili to lectin-resistant clones of Chinese hamster ovary cells.

Pili facilitate the attachment of virulent Neisseria gonorrhoeae to host cells. Isolated pili and peptides from pili obtained by cyanogen bromide cleavage were used in attachment assays to Chinese hamster ovary cells and their lectin-resistant clones. Pili and the largest cyanogen bromide fragment (CNBrI) from the amino-terminal portion of the pilin molecule attached to a greater degree to the parent cell and showed 40 to 75% reduced attachment to clones deficient in cell surface oligosaccharides. The CNBrI fragment, with a molecular weight of approximately 10,000, bound specifically to host proteins with subunit molecular weights of 14,000 to 16,000 that were electrophoretically transferred onto nitrocellulose sheets from polyacrylamide gel patterns of host cells. Periodate or galactosidase treatment of pili or the CNBrI fragment markedly reduced attachment, suggesting the importance of galactose residues on pili for their attachment function. Similarly, highly purified exoglycosidase or trypsin treatment of the parent cell reduced attachment, suggesting that oligosaccharide moieties of cell surface components (glycoproteins or glycolipids or both) were receptors for pili attachment. This study indicated that the portion of the pilin molecule involved in attachment resides on the CNBrI fragment and that sugar moieties, both on pili and on the host cell, were required for optimal attachment.