Lymphoadenopathy during Lyme Borreliosis Is Caused by Spirochete Migration-Induced Specific B Cell Activation
(A, B) Immunohistochemistry with polyclonal B. burgdorferi-specific rabbit serum, demonstrates the presence of extracellular B. burgdorferi spirochete (arrow) in the subcapsular sinus of the right inguinal lymph node of C57BL/6 mice infected by tissue-transplant eight days prior to analysis. (C) Shown are mean cell numbers of right inguinal lymph nodes of C57BL/6 mice (n = 2 per timepoint) either infected via injection of 104 culture-grown live (live) or heat-killed and sonicated B. burgdorferi in PBS. “+” identifies positive B. burgdorferi cultures of lymph nodes (n = 2 per timepoint) from the same group of mice, “−” shows lack of B. burgdorferi growth in culture. Results are from one of two independent experiments that gave similar results. (D–F) Comparison of mice infected as in (C) but injected with 106 inactivated B. burgdorferi for 8 days prior to analysis (D) Total numbers of cells recovered from lymph nodes. Each symbol represents results from one animal; horizontal bars indicate the mean for the group. (E) Data shown are total numbers CD4, CD8 T cells and CD19 B cells calculated from total cell counts and frequencies of cell subsets as determined by flow cytometry. (F) Shown are frequencies of IgG antibody-secreting cells in lymph nodes of mice given live or inactivated B. burgdorferi. Note data are normalized to B cell numbers. Each symbol represents the results from one mouse; the horizontal line indicates the mean for the group.