Neisseria gonorrhoeae That Infect Men Have Lipooligosaccharides with Terminal N-Acetyllactosamine Repeats

Infectious Neisseria gonorrhoeae make relatively large lipooligosaccharides (LOS) that structurally resemble human glycosphingolipids. MS11mkC is an LOS variant of N. gonorrhoeae strain MS11 which was isolated from men at the onset of dysuria (Schneider, H., Griffiss, J. M., Boslego, J. W., Hitchcock, P. J., Zahos, K. M., and Apicella, M. A. (1991) J. Exp. Med. 174, 1601–1605). Delayed extraction matrix-assisted laser desorption and ionization and electrospray ionization mass spectrometry of O -deacylated MS11mkC LOS produced ions consistent with known LOS which have lacto- N -neotetraose (Galβ1→4GlcNAcβ1→3Galβ1→4Glc; paraglobosyl; monoclonal antibodies (mAbs) 1B2 + and 06B4 + ) and GalNAc→lacto- N -neotetraose (gangliosyl; mAb 1-1-M + ) oligosaccharides. Ion peaks for a larger LOS which also bound mAb 1B2 indicated the addition of a hexose (+162 Da) to gangliosyl LOS or the addition of a hexose and a N -acetylhexosamine (+365 Da) to paraglobosyl LOS. Analysis of HF-treated and O -deacylated LOS revealed three major components present in a phosphoethanolamine (PEA) 0 and a PEA 1 series. Digestion of MS11mkC LOS by β- N -acetylhexosaminidase and β-galactosidase, alone and sequentially, combined with mAb binding patterns, confirmed the presence of a nonreducing terminal repeating LacNAc ((Galβ1→4GlcNAc) 2 ) on the largest LOS, rather than a parallel oligosaccharide structure.