Identification by mass spectrometry of CMP-NANA in diffusible material released from high M r blood cell fractions that confers serum resistance on gonococci

Abstract

In previous work, a low M r component from human blood which converts serum-sensitive gonococci to resistance was shown to be indistinguishable from cytidine 5′-monophospho-N-acetyl neuraminic acid (CMP-NANA) by seven criteria. However, the presence of CMP-NANA was not proved by physicochemical methods. Purified, high M r fractions from human blood cells, which confer serum resistance on gonococci and enhance the transfer of sialyl groups from CMP-NANA of lipopolysaccharide (LPS) by a sialyltransferase in gonococcal extracts, were rechromatographed on DEAE Sepharose CL-6B. Both activities co-eluted from the column but on dialysis were found in the diffusate. After desalting the deffusate with Sephadex G10, the presence of CMP-NANA was proved by mass spectrometry. This confirmed previous work and is the first unequivocal demonstration of CMP-NANA in constituents of human blood cells.