Serum, stool and BAL from orally inoculated mice were tested by indirect ELISA for the presence of total IgG, IgG1, IgG2a or IgA to OspA. Purified recombinant OspA was coated at 0.5 mg/ ml on Nunc MaxiSorp TM flat-bottom ELISA plates (eBioscience, San Diego, CA) and indirect ELISA was performed using serum (1:500), stool (1:10) or bronchoalveolar fluid. Anti-mouse IgG, anti-mouse IgG1, anti-mouse IgG2a or anti-mouse IgA horseradish peroxidase-conjugated antibodies (1:2,000) (Jackson Immu-noResearch, West Grove, PA) was used as secondary antibody.