Fig. 2

OspC production by WT and A3/flaB _p::ospC spirochetes in unfed nymphs. Nymphs were artificially infected as larvae with wild-type B. burgdorferi strain B31-A3 (WT) or an isogenic derivative engineered to constitutively express ospC (A3/flaB _p::ospC). Spirochetes in dissected tick midguts were detected by IFA with a polyclonal anti-B. burgdorferi primary antiserum [41] and rhodamine-labeled secondary antibody, while synthesis of OspC was examined using a monoclonal anti-OspC primary antibody [42] and FITC-labeled secondary antibody