A novel synthetic reversible inhibitor of sialidase efficiently blocks secondary but not primary influenza virus infection of MDCK cells in culture.
The sodium salts of 2-difluoromethyl-phenyl-alpha-ketoside of N-acetyl-neuraminic acid (compound 1) and of 4-difluoromethyl-2-methoxy-phenyl-alpha-ketoside of N-acetylneuraminic acid (compound 2) were designed as potential mechanism-based inhibitors of sialidase. In vitro both of these compounds competitively inhibited the sialidases of Clostridium perfringens and of influenza virus A/HK/1/68. Inhibition was irreversible with the sialidase of Clostridium perfringens whereas it was reversible with that of A/HK/1/68. Compound 2 did not inhibit the hemagglutinin of the virus but exhibited significant anti-influenza activity when added to the medium of Madin-Darby canine kidney (MDCK) cells infected by influenza virus. In non-infected MDCK cells no inhibition of cellular sialidase was observed. Compound 2 did not block primary infection, but inhibited the release of progeny virus from infected cells. Even after 8 passages in its presence, no resistant strains were detected. Because of its high Ki (8 x 10(-5) M) compared to the low Ki (1' x 1(-10) M) of 4 guanidino-Neu 5 Ac 2en and its reversible inhibition of viral sialidase, its development as an anti-influenza agent is no longer envisaged. Nevertheless, as a mechanism-based irreversible inhibitor of the bacterial enzyme, it could at least be useful for investigating the intrinsic role of sialidase in infections caused by this strain.
Barrère
B
B
Laboratoire d'Immunochimie, Faculté de Médecine Lyon-Sud, Oullins, France.
Driguez
P A
PA
Maudrin
J
J
Doutheau
A
A
Aymard
M
M
Quash
G
G
D000818:Animals; D000998:Antiviral Agents / Q000494:pharmacology*; D002460:Cell Line; D002470:Cell Survival / Q000187:drug effects; D003016:Clostridium perfringens / Q000187:drug effects / Q000201:enzymology; D004285:Dogs; D004791:Enzyme Inhibitors / Q000494:pharmacology; D006387:Hemagglutination, Viral / Q000187:drug effects; D009980:Influenza A virus / Q000187:drug effects* / Q000201:enzymology / Q000502:physiology; D009439:Neuraminidase / Q000037:antagonists & inhibitors*; D012794:Sialic Acids / Q000494:pharmacology*; D014764:Viral Proteins / Q000096:biosynthesis; D014771:Virion / Q000187:drug effects; D014779:Virus Replication / Q000187:drug effects
C107667:2-difluoromethylphenyl-ketoside-N-acetylneuraminic acid; C107668:4-difluoromethyl-2-methoxyphenyl-ketoside-N-acetylneuraminic acid; D000998:Antiviral Agents; D004791:Enzyme Inhibitors; D012794:Sialic Acids; D014764:Viral Proteins; D009439:Neuraminidase