FIG. 3.

Sequential addition of anti-FAP IgG and FN results in specific blocking of FN binding by M. avium subsp. paratuberculosis. FN (in pH 6 buffer) was added immediately following the addition of graded concentrations of either NRb IgG or anti-FAP IgG to acid-treated M. avium subsp. paratuberculosis. To factor out nonspecific inhibition of FN binding by M. avium subsp. paratuberculosis, an inhibition index was calculated by dividing counts from anti-FAP-treated wells by companion NRb- IgG-treated wells and subtracting this quotient from unity. ■, strain 5781; □, strain 6594. For both panels, data shown represent the mean and standard error of the mean of four replicates for each treatment.