Figure 4. DmAb14m-IT specificity to gangliosides by ELISA. Both parental DmAb14- IT and DmAb14m-IT showed significant reaction signal toward 3′-isoLM1 and 3′,6'-isoLD1 among the different series of gangliosides compared with negative structural control D2C7-IT. SL50 IgM and DmAb22 IgM served as positive controls for 3′-isoLM1 and 3′,6'-isoLD1, respectively, and MOPC served as the negative control IgM to confirm the ganglioside coating. DmAb14 immunotoxins specifically react with 3′-isoLM1 and 3′,6'-isoLD1 by the epitope of the N-acetylneuraminic acid and N-glycolylneuraminic acid side chain with N-acetylglucosamine linked by β1–3 of oligosialogangliosides. The mean values of three experiments (mean ± SD at 450 nm). The structure of all gangliosides tested in the ELISA were illustrated.