FIG. 2.

Influence of BSA (blocking reagent) and divalent cation chelating agents on ELISA. E^rns_{aa 112-227}E1_{aa 1-7} (2 μg/ml) was immobilized on an ELISA plate and reacted with one positive serum (S#3) and one negative serum at 1/50 and 1/100 dilutions. Four assay conditions were examined for each serum dilution: (i) dilution of pig sera in PBST; (ii) blocking of the plate with 3% BSA in PBST prior to adding pig serum (diluted in PBST); (iii) dilution of pig serum in PBST containing EDTA/EGTA (7.5 mM each; pH 6.3); and (iv) blocking of the plate with 3% BSA in PBST prior to adding pig serum (diluted in PBST containing EDTA and EGTA).