Fig. 3.

Receptor and species specificity assay for QH and XJ H5N1. (A) Two analogs of sialic acid, Neu5Acα2-6GalNAcα-PAA-biotin and Neu5Acα2-3GalNAcα-PAA-biotin, were used to determine the receptor specificity. Biotin was used as a negative control. The ELISA assay was repeated more than three times. (B) HeLa and DF-1 cells, from a human and a bird, respectively, were used to compare the infection efficiency of HA and HA mutant pseudotype viruses. Luciferase activities (raw light units [RLU]) of HeLa and DF-1 cells infected with nine HA pseudotype viruses are shown. Data are the mean ± s.d. of three similar experiments run in triplicate