Table 1.

Binding of labeled Ovo (Ovo-HRP) and PM (PM-HRP) to influenza viruses

VirusAssociation constant (U−1)a
Ovo-HRP (Sia2-3Gal)PM-HRP (Sia2-6Gal)
Chicken H5N1
 Ck/HK/220/97 (CHO158)b,c 0.4<0.2
 Ck/HK258/97 (CHO158)b,c 0.5<0.2
 Ck/HK/728/97c 1<0.2
 Ck/HK/786/97 (CHO158)b,c 0.5<0.2
 Ck/HK/915/97c 1<0.2
Human H5N1 isolate HK/156/97c 1.5<0.2
Viruses from aquatic birds
 Dk/HK/205/77 (H5N2)c 2.6<0.2
 Dk/HK/308/78 (H5N2)3.1<0.2
 Dk/HK/698/79 (H5N2)c 3.4<0.2
 Dk/MN/1525/81 (H5N1)c 3.3<0.2
 Gull/PA/4175/83 (H5N1)2.2<0.2
 Dk/Bavaria/1/77 (H1N1)3.6<0.2
 Mallard/MT/61 (H2N2)2.3<0.2
 Dk/Hokkaido/7/82 (H3N8)7.6<0.2
Human pandemic strains
 Aichi/2/68 (H3N2)<0.14
 RI/5+ (H2N2)<0.160
  • a The binding assay was performed, and the association constants of virus complexes with labeled sialylglycoproteins were calculated as described in Materials and Methods. Only the upper limit of Kass could be estimated when the association constants were below 0.1 to 0.2 U−1 because the absorbancy at most experimental points was close to the background level.

  • b These viruses differ from the other H5N1 isolates from 1997 by the presence of a glycosylation sequon at positions 158 to 160 of HA1 (CHO158), which was shown to be glycosylated (40).

  • c Inactivated with BPL.