Threonine 143 in HA blocks neutralizing antibodies binding to antigenic site.

Immunoprecipitation of A/Shanghai/02/2013 HA (A) and A/Netherlands/219/2003 HA (B) with mAb 5A6. The relative levels of HA shown by Western blots were detected with goat antisera against A/Netherlands/219/2003 HA. Percentages of the HA signal intensities, normalized to the 1/10 volume of the input used for the immunoprecipitation (control), are indicated below each blot. Con: control; IP: immunoprecipitation. Data shown are representative of two independent experiments.