Generation of hyperfunctional recombinant human factor IX variants expressed in human cell line SK-Hep-1.
Biotechnol Lett 2020;
43:143-152. [PMID:
33130980 DOI:
10.1007/s10529-020-03040-7]
[Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2019] [Accepted: 10/27/2020] [Indexed: 10/23/2022]
Abstract
OBJECTIVE
To develop recombinant factor IX (FIX) variants with augmented clotting activity.
RESULTS
We generated three new variants, FIX-YKALW, FIX-ALL and FIX-LLW, expressed in SK-Hep-1 cells and characterized in vitro and in vivo. FIX-YKALW showed the highest antigen expression level among the variants (2.17 µg-mL), followed by FIX-LLW (1.5 µg-mL) and FIX-ALL (0.9 µg-mL). The expression level of FIX variants was two-five fold lower than FIX-wild-type (FIX-WT) (4.37 µg-mL). However, the biological activities of FIX variants were 15-31 times greater than FIX-WT in the chromogenic assay. Moreover, the new variants FIX-YKALW, FIX-LLW and FIX-ALL also presented higher specific activity than FIX-WT (17, 20 and 29-fold higher, respectively). FIX variants demonstrated a better clotting time than FIX-WT. In hemophilia B mice, we observed that FIX-YKALW promoted hemostatic protection.
CONCLUSION
We have developed three improved FIX proteins with potential for use in protein replacement therapy for hemophilia B.
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