has role protective antigen role protective antigen Influenza virus protein HA from Influenza A virus (A/Hatay/2004/(H5N1)) Protegen ID: 551; NCBI Protein GI: 56311402; NCBITaxon: 303316 Allen Xiang A neutralizing monoclonal antibody (mAb) 9F4 against the hemagglutinin (HA) of the influenza A/chicken/hatay/2004 H5N1 virus was generated. MAb 9F4 was found to be protective, both prophylactically and therapeutically, against lethal viral challenge of mice [PubMed: 20519402]. Oliver He protein