FIG. 3.
Differential diagnosis to differentiate vaccinated, diseased cattle from vaccinated, protected cattle. IFN-γ responses were determined 16 weeks postchallenge using either ELISPOT (A) or EIA (B) as readout systems. Antigens were as follows: PPD-B (10 μg/ml), recombinant ESAT-6 (5 μg/ml), or a synthetic peptide cocktail (5 μg of each peptide/ml) (51). Filled symbols, BCG-vaccinated animals without signs of disease; shaded symbols, BCG-vaccinated animals with confirmed BTB; open symbols, unvaccinated controls; horizontal lines, cutoffs for positivity as determined by testing of uninfected animals. ISI, IFN-γ stimulation index; ELISA, enzyme-linked immunosorbent assay. SFC, spot-forming cells.