Microneutralization data and differences between A/Moscow/10/1999(H3N2) isolates.

(A) Microneutralization titers for antibody K03.28, S8V1-172, S5V2-107, and S8V2-124. All values are in μg/ml. (B) We note there are 8 amino acid differences between the HA of A/Moscow/10/1999(H3N2) (GenBank DQ487341) used in binding assays (Fig 3) and the A/Moscow/10/1999(H3N2)(X-137) reassortant virus used in microneutralization assays (GenBank CY121381). Their positions are shown in red sticks (145K/N, 158E/K,159N/Y, 190D/V, 194V/L 196V/T, 226I/V, and 246N/K) in the structure of S8V1-172 complexed with the A/Sydney/05/1997(H3N2) HA head domain. K03.28 modeled in through superposition upon their respective HA head domains (not shown). Manual inspection suggests that a subset of mutations found in A/Moscow/10/1999(H3N2) would disrupt HA-Fab contacts at positions 145 and 159 and introduce an unfavorable contact at position 190. Figure data are in S1 Data.

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