Establishment of Stable CHO Cell Line Expressing Recombinant Human Haptoglobin: Toward New Haptoglobin-Based Therapeutics

Intravascular hemolysis occurs in many hematologic disorders which results in free hemoglobin (Hb). Haptoglobin (Hp) is an acute-phase plasma glycoprotein that binds free Hb to prevent its oxidative damages. Due to the safety issues related to the plasma-derived proteins, the production of Hp using recombinant DNA technology is considered as an alternative source. In this study, Hp gene was isolated from HepG2 cell line and cloned into pcDNA3.1(+) vector. Gene cloning was confirmed with colony PCR, restriction digestion and DNA sequencing. CHO cells were transfected with the construct, and finally a stable CHO cell line expressing human recombinant Hp (rHp) was established. The expression of rHp was confirmed with RT-PCR and Western blot analyses both at mRNA and protein levels. This is the first report of establishing a stable CHO cell line expressing human rHp as a primary step toward future rHp clinical applications.