Figure 3. Identification of TcdA-specific mAb pairs to have the optimal detection of TcdA toxin by sandwich ELISA. (A) Screening of mAb pairs of six mAb, using one as the coating antibody (indicated under the columns) and the other as detecting antibody conjugated by HRP (indicated at the right side of the graph). Commercial TcdA toxin (0.05 µg/ml) was used as designated toxin in the ELISA assays. (B) Detection of toxin A with 4 mAb by sandwich ELISA using mAb 1G3 as the coating antibody. (C) Detection of toxin A with 4 mAb by sandwich ELISA using mAb 5G8 as the coating antibody.