Frontiers in Bioscience-Elite (FBE) is published by IMR Press from Volume 13 Issue 2 (2021). Previous articles were published by another publisher on a subscription basis, and they are hosted by IMR Press on imrpress.com as a courtesy and upon agreement with Frontiers in Bioscience.
How a single amino acid change may alter the immunological information of a peptide
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What types of amino acid substitutions are functionally tolerated in an epitope? This question is of importance because the immunogenicity, pathogenicity, and therapeutic potential of a peptide can be determined by a single amino acid change. As an example, a single amino acid change in the encephalitogenic myelin oligodendrocyte glycoprotein WYRSPFSRVV peptide confers the capacity to ameliorate and reverse experimental autoimmune encephalomyelitis. Currently, no rule is available to predict/explain the functional outcomes of amino acid changes. To address this issue, we examined the role of single amino acid changes in immune responses by applying proteomic similarity analyses to available data. We found that the loss or gain of immunological information in a peptide epitope following an amino acid substitution often is related to a gain or loss in the proteomic similarity. Rare, but significant epitopic sequences become immunologically insignificant when an amino acid change makes them common, repeated sequences. This study confirms that low similarity to the host proteome is a major factor in modulating the immune epitope repertoire.