Table 4. Neutralization IC₅₀(μg/ml)of influenza antibodies in MDCK plaque formation assay.

–, no measureable activity; blank not done; ^ only neutralizing if antibody allowed to bind virus prior to activation with trypsin. Group 1 mAb 48 and 49 did not bind to the H2 strain. All of the other antibodies listed in this table showed high affinity binding to the breadth of group 1 or group 2 HA proteins, respectively, corresponding to the viruses tested. Only mAb 486 showed high affinity binding to both group 1 and 2 HA proteins in monomeric and trimeric forms. †All wild bird viruses kindly provided by Dr David Stallknecht (UGA). ‡Reverse genetics virus containing modified H5 and N1 of A/Vietnam/1203/2004 and approved for non-BSL3 containment. Gift of Dr Ruben Donis (CDC).