Case Study on Recombinant Protein Production

 

Figure 1. Expression comparison between a commercial vector from one of major suppliers (1) and the first-version ATGCell vector REEMAC1 (2), for three different proteins (A, B, C and D) stably expressed in CHO cells. Proteins were collected from the culture medium and probed with an epitope antibody in a Western blotting.

 

Figure 2. Expression comparison between the first-version vector REEMAC1 (1) and the second-version vector REEMAC2 (2). REEMAC vectors hosting human interferon-α1 gene were transiently transfected (upper panel) and stably transfected (lower panel) in CHO cells. Expressed proteins were collected from the culture medium and probed with an epitope antibody in a Western blotting.

 

Figure 3. Expression stability analysis among different REEMAC vectors (1. REEMAC2; 2. REEMAC2Q; 3. REEMAC2R). Human interferon α1 was stably expressed in HEK or CHO cells. Stable cell lines were cultured for over a period of time, as indicated. Expressed proteins were collected from the culture medium and probed with an epitope antibody in a Western blotting.

 

Figure 4. Sample proteins stably expressed in HEK cells. Chemokine family: 1 CCL2; 2 CCL3; 3 CCL4; 4 CXCL1; 5 CXCL2; 6 CXCL4; 7 CCL3; Interleukin family (IL): 8 IL5; 9 IL7; 10 IL8; Interferon family (IFN): 11 IFN-α1 ; 12 IFN-α4; Cell surface antigens: 13. CD40; 14 CD54; Cytokine receptors: 15 Tumor necrosis factor receptor type 1; 16 Tumor necrosis factor receptor type 2; 17 Epithelial growth factor receptor; 18 Nerve growth factor receptor; Reporter gene: 19 green fluorescent protein (GFP); Transcription factor: 20 P53; Protein kinases: 21 MAP kinase-3; 22 Protein kinase A α-subunit; 23 Cyclin-dependent kinase-2.

 

Figure 5. Purified sample proteins. Coomassie staining of interferon-α1, chemokine CXCL1 and interleukin-5 (tagged), nerve growth factor and two monolconal antibodies (tag-free) after single-column affinity purification.
 

Protein Name Yield in HEK Cells(pg/cell/day) Yield in CHO Cells(pg/cell/day)
Chemokine CCL2 115 101
Chemokine CCL4 89 55
Chemokine CCL5 50 49
Chemokine CXCL1 97 54
Chemokine CXCL2 84 38
Chemokine CXCL4 93 28
Chemokine CXCL5 90 23
Chemokine CXCL7 80 36
Interleukine-2 86 27
Interleukine-8 107 27
Interferon-α1 80 24
Interferon-α4 118 20
Insulin-like growth factor-2 102 37
Nerve growth factor 31 45
Bone morphogenetic protein-2 35 8
Transforming growth factor-β1 18 23
Human mAb1 45 37
Mouse mAb1 40 32
Rabbit mAb1 43 31

Table 1. Expression levels of sample proteins stably expressed in HEK and CHO cells.