Antibody epitopes on the neuraminidase of a recent H3N2 influenza virus (A/Memphis/31/98).
We have characterized monoclonal antibodies raised against the neuraminidase (NA) of a Sydney-like influenza virus (A/Memphis/31/98, H3N2) in a reassortant virus A/NWS/33(HA)-A/Mem/31/98(NA) (H1N2) and nine escape mutants selected by these monoclonal antibodies. Five of the antibodies use the same heavy chain VDJ genes and may not be independent. Another antibody, Mem5, uses the same V(H) and J genes with a different D gene and different isotype. Sequence changes in escape mutants selected by these antibodies occur in two loops of the NA, at amino acid 198, 199, 220, or 221. These amino acids are located on the opposite side of the NA monomer to the major epitopes found in N9 and early N2 NAs. Escape mutants with a change at 198 have reduced NA activity compared to the wild-type virus. Asp198 points toward the substrate binding pocket, and we had previously found that a site-directed mutation of this amino acid resulted in a loss of enzyme activity (M. R. Lentz, R. G. Webster, and G. M. Air, Biochemistry 26:5351-5358, 1987). Mutations at residue 199, 220, or 221 did not alter the NA activity significantly compared to that of wild-type NA. A 3.5-A structure of Mem5 Fab complexed with the Mem/98 NA shows that the Mem5 antibody binds at the sites of escape mutation selected by the other antibodies.
Gulati
Upma
U
Department of Biochemistry and Molecular Biology, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma 73104, USA.
Hwang
Chi-Ching
CC
Venkatramani
Lalitha
L
Gulati
Shelly
S
Stray
Stephen J
SJ
Lee
Janis T
JT
Laver
W Graeme
WG
Bochkarev
Alexey
A
Zlotnick
Adam
A
Air
Gillian M
GM
D000595:Amino Acid Sequence; D000818:Animals; D000911:Antibodies, Monoclonal / Q000235:genetics; D000914:Antibodies, Viral / Q000235:genetics; D000956:Antigens, Viral / Q000235:genetics; D001665:Binding Sites / Q000235:genetics; D003429:Cross Reactions; D018604:Epitope Mapping; D000939:Epitopes / Q000235:genetics; D005803:Genes, Immunoglobulin; D005814:Genes, Viral; D006801:Humans; D007140:Immunoglobulin Fab Fragments / Q000235:genetics; D053122:Influenza A Virus, H3N2 Subtype; D009980:Influenza A virus / Q000201:enzymology* / Q000235:genetics / Q000276:immunology*; D051379:Mice; D008958:Models, Molecular; D008969:Molecular Sequence Data; D009154:Mutation; D009439:Neuraminidase / Q000737:chemistry / Q000235:genetics / Q000276:immunology*; D011487:Protein Conformation
D000911:Antibodies, Monoclonal; D000914:Antibodies, Viral; D000956:Antigens, Viral; D000939:Epitopes; D007140:Immunoglobulin Fab Fragments; D009439:Neuraminidase