Recombinant BBK32 protein in serodiagnosis of early and late Lyme borreliosis

Borrelial protein BBK32 was evaluated as an antigen in the serodiagnosis of early and disseminated Lyme borreliosis (LB). bbk32 was cloned and sequenced from eight isolates of the three pathogenic Borrelia species. The identities between the amino acid sequences of the BBK32 proteins from Borrelia burgdorferi sensu stricto, B. garinii, and B. afzelii isolates were 71 to 100%. By immunoglobulin G (IgG) Western blotting or enzyme-linked immunosorbent assay (ELISA), up to 74 and 100% of acute- and convalescent-phase samples, respectively, from 23 patients with erythema migrans (EM) were positive for recombinant BBK32 protein from B. afzelii. In the serology of disseminated LB, the three variant BBK32 antigens cross-reacted. In total, 14 of 14 samples from patients with neuroborreliosis and 15 of 15 samples from patients with Lyme arthritis were positive. The specificities of the IgG ELISA with the variant BBK32 antigens for EM and disseminated borreliosis were 81 to 92% and 89 to 95%, respectively. Our findings indicate that the BBK32 proteins are promising serodiagnostic antigens for the detection of early and disseminated LB but that variant BBK32 proteins may be needed either in parallel or in combination with an immunoassay for LB to cover all the relevant borrelial species that cause the disease.