Immunogen: Synthesized 23-amino acid peptide, SLLTEVETPTRSEWECRCSDSSD, the ectodomain of matrix protein 2 (M2e) of the influenza virus swine flu strain (A/California/06/2009/H1N1) virus (GenBank accession# ACP41938). Specificity: Reacts with the matrix protein 2 of influenza A that contains the same ectodomain sequence.