Significantly Improved Detection of Early Lyme Disease by Peptide ELISA Based on the Borreliacidal Antibody Epitope of Borrelia burgdorferi OspC

Microbiology Research Laboratory, and Department of Medical Research, Gundersen Lutheran Medical Foundation and Section of Infectious Diseases, Gundersen Lutheran Medical Center, La Crosse, Wisconsin 54601 and Wisconsin State Laboratory of Hygiene, Madison, Wisconsin 53706

^* To whom correspondence should be addressed. Email: SMCallis{at}gundluth.org.

	Abstract

Highly specific borreliacidal antibodies are induced by infection with Borrelia burgdorferi, and the immunodominant response during early Lyme disease is specific for an epitope within the 7 amino acids nearest the C-terminus of OspC. We evaluated the ability of an enzyme-linked immunosorbent assay (ELISA) based on a synthetic peptide (OspC7) that matched the region to detect the response and compared the sensitivity during early Lyme disease to an FDA-approved Western blot. When the OD value was adjusted to 98% specificity based on the results from testing normal or uncharacterized sera (n = 236) or sera from patients with blood factors or illnesses that commonly produce antibodies that cross-react with B. burgdorferi antigens (n = 77), 115 (73%) of 157 sera from patients likely to have early Lyme disease were positive for immunoglobulin (IgM) antibodies and 17 (11%) also had IgG antibodies. In addition, the IgM ELISA reactivities and the titers of antibodies detected by a flow cytometric borreliacidal antibody test correlated closely (r = 0.646). Moreover, the IgM ELISA was significantly more sensitive (p < 0.001) than the Western blot. The findings therefore confirmed the peptide IgM ELISA detected OspC borreliacidal antibodies and provided strong evidence the test can eliminate the necessity for confirming early Lyme disease by a supplementary test such as Western blot.