Western blot of Hemagglutinin using recombinant seasonal Hemagglutinin (lanes A & B) and swine-origin Hemagglutinin (lanes C & D) with anti-seasonal Hemagglutinin antibody (LS-C108541) at 2 ug/ml (lanes A & C) and anti-swine-origin Hemagglutinin antibody (LS-C108542) at 2 ug/ml (lanes B & D). Below: Seasonal Hemagglutinin antibody at 2 ug/ml specifically recognizes seasonal influenza virus A H1N1 but not swine-origin influenza virus (S-OIV) A H1N1 Hemagglutinin protein. ELISA results using Seasonal H1N1 Hemagglutinin antibody at 1 ug/ml and the blocking and corresponding peptides at 50, 10, 2 and 0 ng/ml.