Double-labeling IFAs of B. burgdorferi. (A) Specificity of MAb B11 for ErpA/I/N and of each polyclonal antibody raised against ErpB/J/O, ErpG, ErpK, ErpL, ErpM, ErpP, ErpX, and ErpY. Bacteria were cultured at 34°C, and lysates were analyzed by immunoblot with each antibody preparation. Number of kilodaltons is given on left. (B) IFA of fixed B. burgdorferi labeled with MAb B11 (left column) and labeled with a polyclonal antibody against a specific Erp protein (middle column). Both IFAs were analyzed (right column).