Antibodies that specifically bind to a peptide having an amino acid sequence as found at the N-terminus of the HA2 fusion peptide of the influenza A virus may be raised by inoculating a mammal with a conjugate of the peptide. In one embodiment, the conjugate comprises the peptide linked to a spacer (e.g. 6-aminocaproic acid) and a carrier protein (e.g. KLH). The antibodies may be used as a universal reagent for detecting HA proteins of influenza viruses. The antibodies are useful as versatile reagents for laboratory research and vaccine potency determination, especially in the event of pandemic influenza outbreaks.