Evaluation of whole-cell and OspC enzyme-linked immunosorbent assays for discrimination of early lyme borreliosis from OspA vaccination.

A recombinant Lyme borreliosis vaccine consisting of outer surface protein A (OspA) is commercially available for vaccination of humans against infection with Borrelia burgdorferi. Vaccination with OspA induces an antibody response that makes serologic interpretation of infection with B. burgdorferi difficult, especially by screening tests based on whole-cell preparations of B. burgdorferi. We show that an enzyme-linked immunosorbent assay with B. burgdorferi sensu stricto 50772, which lacks the plasmid encoding OspA and OspB, or a full-length recombinant OspC protein can identify patients infected with B. burgdorferi. We found that 69 and 65% of serum samples from patients with case-defined early Lyme borreliosis had anti-B. burgdorferi sensu stricto 50772 and anti-OspC reactivities, respectively. In addition, little or no reactivity was detected with sera obtained from individuals vaccinated with OspA. Unfortunately, 51 and 33% of sera from healthy patients and sera from patients with other illnesses were also reactive against B. burgdorferi sensu stricto 50772 and OspC, respectively. Although these assays can discriminate B. burgdorferi infection from vaccination with OspA, their lack of specificity highlights the necessity for confirming equivocal or positive reactivities with more specific serodiagnostic tests.