The DBA/1 Strain Is a Novel Mouse Model for Experimental Borrelia burgdorferi Infection

Lyme arthritis, caused by Borrelia burgdorferi, has similarities to rheumatoid arthritis and its experimental murine model, collagen-induced arthritis (CIA). Currently, no common strain exists for examination of arthritis models of Lyme arthritis and CIA, which are typically studied in C3H/HeJ and DBA/1 mice, respectively. The aim of this study was to define the characteristics of Borrelia burgdorferi infection and arthritis in the DBA/1 murine strain. Murine Lyme arthritis was induced in C3H/HeJ and DBA/1 mice by subcutaneous infection with B. burgdorferi. Tibiotarsal joints were measured during infection, and mice were sacrificed for histologic, microbiologic, and serologic analysis on days 14 and 42 postinfection. All bladder cultures obtained from C3H/HeJ and DBA/1 mice at 14 days postinfection grew Borrelia. There was no significant difference in spirochetal burdens in hearts and tibiotarsal joints at days 14 and 42 postinfection. Tibiotarsal joint swelling and histologic scoring were not significantly different between the two strains. Serologic analysis revealed increased IgG2a production in C3H/HeJ mice compared to DBA/1 mice. Analysis of 2-dimensional immunoblots revealed several specific antigens (LA7, BBA03, BBA64, BBA73, OspA, and VlsE) which were not recognized by DBA/1 sera. We conclude that the DBA/1 murine strain is a suitable model for the study of Lyme arthritis and experimental B. burgdorferi infection, allowing direct comparison between Lyme arthritis and collagen-induced arthritis. The specificity of the humoral immune response differs between the two strains, further study of which may reveal important findings about how individual strains respond to B. burgdorferi infection.