Table 2

Cross-reactivity of antisera determined by OD values from neuraminidase inhibition assays

NA subtypeNo. of virusesaAIVs showing cross-reactivity with rNA antisera by OD valueb
rN1rN2rN3rN4rN5rN6rN7rN8rN9
N19+
N292+
N37+
N43111+1111
N531+
N69+
N75+
N89+
N95+
  • a These AIVs are presented in Table 1, except for the reference AIVs.

  • b Antisera were produced in this study. We defined cross-reactivity as a neuraminidase inhibition rate that was more than 30% with a 1:100 dilution of serum. +, significant inhibition; −, no cross-reactivity. The numbers indicate the numbers of AIVs among the subtypes that showed cross-reactivity with the antiserum.