Identification of sequence similarities between Mycobacterium leprae and the myelin proteolipid protein by computational analysis.

This study was undertaken under the assumption that antigenic mimicry plays a role in the pathogenesis of neuropathy in leprosy, a unique feature among mycobacterial diseases. The SWISS-PROT protein sequence databank was scanned using a computer programme based on an identity matrix algorithm, to identify common amino acid regions between human myelin and mycobacterial proteins. The highlighted motifs were back-tested against a database of MHC-binding peptides (MHCPEP). Of the 28 common sequences between mycobacterial and human myelin proteins, only two were found to yield some matches with MHC-presenting peptides. Both motifs were from M.leprae. The myelin proteolipid protein was the human protein containing the identified similarities. We believe that this theoretical approach can provide a way to predict potentially "mimetic" motifs by search for antigenic regions in protein sequence databases without screening a large number of synthetic peptides.