Figure S1 - Comparison of Internal Ribosome Entry Site (IRES) and Furin-2A (F2A) for Monoclonal Antibody Expression Level and Quality in CHO Cells

Peptide mapping of tryptic peptides of LC and HC expressed from the four tricistronic vectors. Protein A purified product from duplicated stable transfection pools of each vector were analyzed. Purified samples from each pool were reduced and separated on SDS-PAGE. The bands (refer Figure 5) were excised for LC-MS/MS analysis. Sequences highlighted in green denote the tryptic peptides detected by LC-MS/MS. Underlined amino acid sequences are either signal peptide or F2A peptide. (A) Sample 1 and 2 produced from H-F2A-L vector corresponding to excised gel band at 80 kDa. (B) Sample 1 and 2 produced from H-F2A-L vector corresponding to excised gel band at 55 kDa band. (C) Sample 1 and 2 produced from H-F2A-L vector corresponding to excised gel band at 50 kDa band. (D) Sample 1 and 2 produced from H-F2A-L vector corresponding to excised gel band at 25 kDa band. (E) Sample 1 and 2 produced from L-F2A-H vector corresponding to excised gel band at 80 kDa band. (F) Sample 1 and 2 produced from L-F2A-H vector corresponding to excised gel band at 50 kDa band. (G) Sample 1 and 2 produced from L-F2A-H vector corresponding to excised gel band at 30 kDa band. (H) Sample 1 and 2 from H-IRES-L vector corresponding to excised gel band at 50 kDa band. (I) Sample 1 and 2 produced from H-IRES-L vector corresponding to excised gel band at 25 kDa band. (J) Sample 1 and 2 produced from L-IRES-H vector corresponding to excised gel band at 50 kDa band. (K) Sample 1 and 2 produced from L-IRES-H vector corresponding to excised gel band at 25 kDa band. (DOC)