Influenza A virus-binding activity of glycoglycerolipids of aquatic bacteria

As the aqueous sphere has been proposed to be an important source medium fo r the virus infection of land animals, the glycolipids of some aquatic orga nisms were examined for human influenza A virus-binding activity. Active co mpounds were not found among the eight echinoderm gangliosides, but two act ive non-sialylated glycoglycerolipids were isolated from an aquatic bacteri um, Corynebacterium aquaticum. The structural formula of one of them, H632A , was elucidated to be1-14-methyl-hexadecanoyl-3-alpha-D-galactopyranosyl-( 1-->3)-6-( 12-methyl-tetradecanoyl)-1-alpha-D-mannopyranosyl-sn-glycerol, T he latter together with reported one elsewhere, S365A, 1-14-methyl-hexadeca noyl-3-[alpha-D-mannopyranosyl-(1-->3)-6-(12-methyl-tetradecanoyl)-1-alpha- D-mannopyranosyl]-sn-glycerol, apparently bound to three human influenza vi ruses, A/PR/8/34 (H1N1), A/Aichi/2/68 (H3N2), and A/Memphis/1/71 (H3N2), ex hibiting 7-12% (H632A) and 10-22% (S365A) of the activities of the control substances (Neu3Ac alpha 2-3-paragloboside and Neu5Ac alpha 2-6-paraglobosi de), Additionally, these glycolipids were assumed to have virus-neutralizin g activities for the following two reasons: (i) The hemagglutination and he molysis activities of the viruses were inhibited by the glycolipid. (ii) Th e leakage of a cytosolic enzyme (lactate dehydrogenase) from Madin-Darby ca nine kidney cells on virus infection was prevented by the glycolipids to ne arly the same extent as by fetuin. This is the first evidence of the bindin g- and neutralizing-abilities of native glycoglycerolipids as to influenza viruses.