Variant responses of mice to Borrelia burgdorferi depending on the site of intradermal inoculation.

C3H/He mice inoculated intradermally at one of two sites with Borrelia burgdorferi responded differently to infection. Shoulder-inoculated mice developed spirochetemia, B. burgdorferi-specific antibody, and arthritis earlier than foot-inoculated mice. Lymphocyte populations derived from spleen tissue were elevated in the shoulder- but not the foot-inoculated mice, and those from lymph nodes were increased in both groups. Lymphocytes derived from blood and spleen tissue showed impaired proliferative responses to all mitogens for shoulder-inoculated mice only, whereas proliferation of lymph node cells was not affected, regardless of route. These results demonstrate that the site of initial B. burgdorferi inoculation is an important determinant in the pathogenesis of B. burgdorferi infection.