Borrelia afzelii and immune response of BALB/c mice

The aim of our study was to find a possible existence of various vaccination effects on the formation of antibodies against three individual Borrelia afzelii strains (dead cell suspension) isolated from a vector, potential vector and host of this spirochaete, which makes this experiment unique in the research of Lyme disease causative agents. Three strains of Borrelia afzelii were isolated from three different sources: Ixodes ricinus tick (BRZ 9), Culex (Culex) pipiens molestus mosquito (BRZ 14) and Apodemus flavicollis wild rodent (BRZ 21). Vaccination induced formation of IgM and IgG in the BALB/c mice (males) and these antibodies were detected in the serum by the Enzyme-Linked ImmunoSorbent Assay (ELISA). IgM antibodies were significantly increased in the mice immunized with BRZ 21 in the third sera testing (P < 0.001) and IgG antibodies in the mice immunized with the BRZ 9 and BRZ 21 strains (P < 0.01) during the whole three-sample collection. Significant differences were found in antibody concentration by comparison of groups immunized with BRZ 9/BRZ 21 and BRZ 14 (P < 0.001), probably caused by the amount of antigen of BRZ 14 strain. Such finding implies that the immune system of the host (rodent), attacked by the same genospecies of pathogenic borreliae (B. afzelii) coming from different sources reacts with the same intensity. This is the first study of reaction of the same borrelian antigen mixture coming from various sources. Borrelia burgdorferi sensu lato, serum, immunization, ELISA In Europe, at least three human pathogenic species of Borrelia burgdorferi sensu lato are responsible for Lyme disease (Baranton et al. 1992). Human pathogenic European strains of Borrelia burgdorferi sensu lato are much more heterogeneous than those of human pathogenic strains found in the United States. Borrelia afzelii belongs among the European strains (Wang et al. 1999). We successfully isolated three strains of Borrelia afzelii from three different sources: Ixodes ricinus ticks as a vector, Culex (Culex) pipiens molestus mosquitoes as a potential vector, and Apodemus flavicollis wild rodent as a reservoir of Borrelia burgdorferi life cycle. According to protein profiles characterization using the gradient Sodium Dodecyl Sulphate Polyacrylamide Gel Electrophoresis (SDS-PAGE), all proteins from 7 up to 200 kDa of all three isolated strains appeared to be the same. Characterization of these strains was also performed by protein profiles comparison with B. burgdorferi sensu stricto and B. garinii. The aforementioned fact about protein identity led us to investigate a response of the immune system to three strains of the same genospecies from three different sources in mammals. The aim of this study was to inoculate the whole homologous cell antigens and to find differences in the creation of IgM and IgG antibodies. Materials and Methods