Dogs vaccinated with common Lyme disease vaccines do not respond to IR6, the conserved immunodominant region of the VlsE surface protein of Borrelia burgdorferi.

A 25-amino-acid synthetic peptide (C(6) peptide) derived from an immunodominant conserved region (designated IR(6)) of the VlsE protein of Borrelia burgdorferi has been identified and used to construct immunoenzyme-based diagnostic procedures. These procedures have excellent sensitivity and specificity. Previous reports have demonstrated the usefulness of the C(6) peptide as an antigen for the serodiagnosis of human and canine Lyme disease.