The neuraminidases of MDCK grown human influenza A(H3N2) viruses isolated since 1994 can demonstrate receptor binding

Table 1 Minimum NAI concentration required to completely inhibit agglutination of chicken RBCs in the NAI-HI assay

Influenza Isolates	Passage ^a	Oseltamivir ^b (nM)	Zanamivir ^b (nM)
*Human*
B/Perth/211/2001	MDCKx	-^c	-
A/Mississippi/3/2001 H1N1	MDCKx	-	-
A/England/23/2002 H1N2	Ex/E1	-	-
A/England/23/2002 H1N2	MDCKx/MDCK1	-	-
A/Lipetsk/14/2002 H3N2	MDCKx	1-10	10-100
A/Okayama/23/2004 H3N2	MDCKx/MDCK1	10	100
A/Brisbane/22/2006 H3N2	MDCKx/MDCK1	1	10
*Swine and Avian*
A/Swine/Nakorn Patham/2002 H3N2	Ex/E2	-	-
A/Duck/Selangor/659/2004 H3N2	Ex/E1	-	-
A/Duck/Tasmania/297/2006 H3N8	E2	-	-
A/Mallard/South Korea/12A/2006 H5N2	E4	-	-
A/Duck/Tasmania/277/2007 H7N2	E4	-	-
A/Chicken/Malacca/4905/2003 H9N2	Ex/E2	-	-

^aE = egg, MDCK = Madin-Darby Canine Kidney, number of passages in culture condition stated or (x) unknown number of passages.
^bNAI-HI assays were performed in duplicate with 4 HAUs of virus, a final concentration of 0.5% chicken RBCs and log₁₀ dilutions of NAIs. Where consecutive drug dilutions showed partial then full inhibition a range between these two is given.
^cNo inhibition of haemagglutination (−) when tested with a maximum of 100,000 nM NAI.

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