Fig. 2

Checkerboard for optimization of the indirect ELISA assay using the recombinant MBP-IpaJ. The coating antigen MBP-IpaJ was added into the well of the ELISA plate at concentrations of 800 ng, 400 ng, 200 ng, 100 ng, 50 ng, 25 ng, and 12.5 ng. Hundred microliters of the antisera used was added per well with dilutions from from 1:10 to 1:5120. The inflection point at 400 ng of MBP-IpaJ and 1:40 dilution of antiserum was considered to represent the optimum concentrations