Lacto- and ganglio-series glycolipids are adhesion receptors for Neisseria gonorrhoeae

Abstract

The role of glycolipids as adhesion receptors for Neisseria gonorrhoeae is examined. Serum-resistant isolates, piliated and nonpiliated isogenic variants, as well as gonococci deficient in lipooligosaccharide and protein II, bind specifically to terminal and internal GlcNAc beta 1-3Gal beta 1-4Glc and GalNAc beta 1-4Gal beta 1-4Gcl sequences in lacto- and ganglio-series glycolipids, respectively, as measured by overlaying glycolipid chromatograms with 125I-labeled organisms. The binding activity was not affected by changing the growth conditions of the organism, as the gonococci bound to both classes of glycolipids when grown anaerobically, microaerophilically on agar or in broth, or under iron-limited conditions. The gonococci do not bind to lacto-sylceramide (Gal beta 1-4Glc beta 1-1Cer) derived from lacto-N-triaosylceramide or from asialo-GM2 by treatment with N-acetyl-beta-hexosaminidase, or to other neutral glycolipids tested. Although N. gonorrhoeae bound weakly to some gangliosides on thin-layer chromatograms, including sialylparagloboside and GM1, in solid phase assays the gonococci bound with high avidity to the sequence GalNAc beta 1-4Gal beta 1-4Glc, with moderate avidity to the sequence GlcNAc beta 1-3Gal beta 1-4Glc, and not at all to gangliosides. Interestingly, the 4.8-kDa component of gonococcal lipooligosaccharide, which contains lacto-N-neotetraose (Gal beta 1-4GlcNAc beta 1-3Gal beta 1-4Glc), strongly inhibits gonococcal-specific agglutination of human erythrocytes and inhibits the binding of labeled organisms to human paragloboside and lacto-N-triaosylceramide on thin-layer chromatograms. Possibly, this binding specificity explains why gonococci autoagglutinate in vitro.