Fig 1: Recombinant DP-C and the specificity of the DP-C affinity purified IgG. (A) Scheme chart of desmoplakin. DP-C was started from aa1945 to aa2871 containing plakin repeat domains A, B, and C. (B) Recombinant protein DP-C on SDS-PAGE stained by Coomassie brilliant blue, and the molecular mass is about 106 kDa. (C) IP-IB assay confirmed the specificity of the DP-C affinity purified IgG. In the IP assay before the IB assay, the extract of HaCat cells was the substrate. The left panel C1-5 showed the IB process with commercial monoclonal antibodies against desmoplakin. C1: IP complex of another commercial anti-desmoplakin antibody; C2: total protein of HaCat as positive control; C3: the IP complex of DP-C affinity purified IgG; C4: the IP complex of N-terminus of desmoplakin affinity purified IgG; C5: the IP complex of healthy donor IgG. Bands of 250 kDa and 210 kDa were detected in the IP complex of DP-C purified IgG (C3) the same as C1, C2, and C4. The right panel C6-11 revealed in the IB process bands expected to be 130 kDa were detected by the monoclonal antibody against desmoglein 3. C6: total protein of HaCat cells as positive control; C7: IP complex of another commercial monoclonal anti-desmoglein 3 (DSG3) IgG; C8: IP complex of normal mouse IgG; C9: IP complex of DP-C affinity purified IgG; C10: IP complex of N-terminus of desmoplakin affinity purified IgG; C11: IP complex of healthy donor IgG. The band of Dsg3 was negative in the complex of DP-C purified IgG (C9), the same as the negative control (C11 and C10). (D) The OD450 value of a group of six healthy donors, five PNP with anti-desmoglein 3, one PNP without (w/o) anti-desmoglein 3, and purified anti-DP-C IgG was determined using an ELISA test of anti-Dsg3 IgG. The OD450 value of anti-DP-C was lower than the value of group of PNP IgG with anti-desmoglein 3, and equal to the PNP IgG w/o anti-demoglein 3, close to the healthy donors.