Fig. 1

Serological detection of specific anti-B. divergens IgG antibodies by Western blot (WB). Panel a: WB was prepared by using B. divergens (Rouen 87) and non-infected human erythrocyte protein extracts. Blots were incubated with sera of patients infected with B. burgdorferi s.l. and positive and negative controls. Lanes 1–40: different B. divergens proteins, ranging from 25 to 75 kDa, that were identified from serum patient samples. Protein bands differed in number, frequency, size and intensity between patients. Lanes 41–47: some of the serum samples from patients infected with B. burgdorferi s.l. that did not recognize B. divergens proteins. Lanes 48–53 and lines C1+, C2+ and C3+: Some of the serum samples and positive controls that did not recognize erythrocyte proteins. Serum samples that reacted against a native B. divergens protein with ~ 37 kDa (*). Serum samples that reacted against native B. divergens proteins of ~ 48–63 kDa (+). Panel b: WB was prepared by using the recombinant GST-rBd37 (Rouen 87) protein and the GST fusion partner for Bd37. Specificity from the patients’ sera against recombinant Bd37 from B. divergens was observed by WB. Lanes A and B: GST-rBd37 (59.5 kDa) and GST (26 kDa) recombinant proteins, respectively, subjected to SDS-PAGE. The number of the lanes indicates which serum sample from Panel a recognized the GST-rBd37 protein. Positive control 1 (C1+): serum sample from an Asturian patient [23]. Positive control 2 (C2+): serum sample from a non-Asturian Spanish patient co-infected with HIV and B. divergens [25]. Positive control 3 (C3+): serum sample from a Finnish patient doubly infected with B. burgdorferi s.l and B. divergens. Negative control (C−) consisted of a human sera pool negative for different infectious diseases, including toxoplasmosis, malaria and babesiosis. None of the sera reacted with the recombinant GST protein