A new specific serodiagnosis system for Lyme disease: use of synthetic peptides derived from outer surface protein C of Borrelia burgdorferi

A new specific serodiagnosis system for Lyme disease was developed using the highly specific partial peptide of outer surface protein C of Borrelia burgdorferi. Finally three peptides (OspC-I, -II and -III) were selected from the outer surface protein C (OspC) amino acid sequence of Borrelia burgdorferi sensu lato and were synthesized. OspC-I is located in the region that is conserved among species of Lyme disease spirochetes, whereas OspC-II and -III are located in the variable regions of the OspC from B. garinii type strain 20047. An enzyme-linked immunosorbent assay (ELISA) to detect antibodies against these synthetic peptides was carried out using sera from patients with Lyme disease. Furthermore, sera from patients with syphilis, tsutsugamushi disease and rheumatoid arthritis were used as control sera to demonstrate specificity of each peptide in the ELISA. The results showed that the false positive results in control sera of OspC-I, -II and -III ELISA for immunoglobulin M (IgM) antibody were 8, 22 and 16%, and those for IgG antibody were 11, 43 and 35%, respectively. These results suggested that the ELISA using OspC-I was the most specific. Therefore, sera from patients with Lyme disease were tested OspC-I ELISA. Of the 21 patients, 12 were in the acute phase and nine in the convalescent phase, 17 (81%) were positive by IgM or IgG ELISA. The sensitivities of IgM and IgG ELISA were 83 and 33% for acute-phase sera, and 22 and 78% for convalescent-phase sera, respectively, suggesting that the IgM response to OspC-I peptide was often detectable in the early stage of infection. Our data demonstrated that OspC-I was one of the common epitopes among species of Lyme disease spirochetes, and therefore this is a suitable antigen for serodiagnosis of early stage Lyme disease with high specificity.