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. 2006 May;13(5):535–540. doi: 10.1128/CVI.13.5.535-540.2006

FIG. 1.

FIG. 1.

Effect of formaldehyde treatment on the ability of IgG in bovine serum to bind to whole organisms or to sonicated antigens of Mycobacterium avium subsp. paratuberculosis in an ELISA. The ELISA was conducted using whole cells (WELISA) (A) and sonicated antigens (SELISA) (B). M. avium subsp. paratuberculosis bacilli were treated with distilled water or 37% formaldehyde and not sonicated (A) or sonicated for 2 s and with the supernatant collected (B) immobilized via evaporation to the wells of 96-well plates. Immobilized M. avium subsp. paratuberculosis antigens were then treated with M. avium subsp. paratuberculosis-positive (solid bars) or -negative (cross-hatched bars) serum and then treated with biotinylated anti-bovine IgG polyclonal antibody. Controls (open bars) consisted of M. avium subsp. paratuberculosis treated with distilled water or formaldehyde and then secondary biotinylated antibody and HRP-streptavidin only. Each bar represents the mean + standard deviation of five replications. In both the WELISA and SELISA, treatment with formaldehyde minimized nonspecific antibody reactions. This experiment was repeated three times with similar results.