A recombinant protein is a protein produced by introducing a gene of interest into a host cell — such as CHO, E. coli, or HEK293 — using recombinant DNA technology, enabling the host to express the desired protein at industrial scale. Recombinant proteins are the most widely manufactured class of biopharmaceuticals, encompassing monoclonal antibodies (mAbs), enzymes, hormones, growth factors, cytokines, and clotting factors. Their production requires careful expression system selection, upstream process development, downstream purification, and rigorous analytical characterization to ensure the required safety, efficacy, and critical quality attributes (CQAs).
