CHRONIC LYME BORRELIOSIS IN THE LABORATORY MOUSE

C3H/HeJ mice were inoculated intraperitoneally with 10(7) uncloned Bor relia burgdorferi at 4 weeks of age and examined on days 30,90,180, an d 360. Spirochetes were isolated from multiple tissues at all interval s. Joint and heart disease were present in all mice at 30 days and res olved after 90 days. At 180 and 360 days, some mice had mild recurrent joint and heart disease, and most bad peripheral segmental periarteri tis. The protein electrophoretic migration of 360-day isolates differe d from the original inoculum. The experiment was repeated with C3H/HeN and BALB/cByJ mice inoculated intradermally with 10(4) cloned B. burg dorferi Characterization of infection and disease at 180 and 360 days were similar to those of the first experiment, but spirochetal protein s of isolates from both intervals displayed no protein variation in el ectrophoretic mobilities. Spirochetes isolated at 360 days were fully pathogenic in naive mice. Sera from infected mice showed an initial im munoglobulin M response, followed by a sustained immunoglobulin G resp onse, involving IgG1, IgG2a, IgG2b and IgG3, with expanding reactivity against multiple antigens over time. These results indicate that immu nocompetent mice sustain persistent infections and develop early acute joint and heart lesions that resolve and then recur intermittent