TABLE 1.

Effect of amino acid changes in the HA of A/Vietnam/1203/04 (H5N1) virus on the antigenic specificity of escape mutants

Escape mutantHA amino acid changeaReactivity with MAbb:
H3 numberingH5 numberingVN04-2VN04-8VN04-9VN04-10VN04-13VN04-15VN04-16777/1
m2(1)S126Y, I155TS121Y, I151T<0000000
m2(4)R166GR162G<0000000
m8(9)K144EK140E0<000<0−2
m9(5)K156EK152E00<<00<<
m9(6)T160A, K193ET156A, K189E00<0<00<
m10K156EK152E00<<00<<
m13(13)S145FS141F0<00<<0<
m13(16)D187N, K193ED183N, K189E00<0<−10<
m15(17)S145PS141P0<00−2<0<
m15(20)G143EG139E0<000<00
m16K156NK152N00<<00<<
m777/1(2)S145PS141P0<00−2<0<
m777/1(4)S145TS141T0<000−20<
  • a Amino acid numbering is based on H3 HA and H5 HA (6).

  • b Values are the differences in log2 units between the HI titers of MAbs in reactions with the wild-type VNH5N1-PR8/CDC-RG (H5N1) virus and with its escape mutants. 0, The HI titer of the MAb does not differ from the titer with the wild-type virus. <, The HI titer at least 32-fold (5 log2) less than the titer with the wild-type virus.