The influenza A linear peptide epitopes recognized by murine antibodies, and currently cataloged at http://www.immuneepitope.org, were examined for the identity score to the host mouse proteome. It was found that almost all of the linear viral determinants are (or contain) regions formed by pentapeptide fragments with no or only very low similarity to the murine proteins. The present study adds to previous reports in suggesting a main role of amino acid sequence similarity in the modulation and definition of the B-cell epitope repertoire, inspiring innovative vaccine approaches able to avoid cross-reactive autoimmune collateral phenomena, and addressing future research in the study of immunity against the influenza A virus and infectious diseases in general.