Chinese hamster ovary (CHO) is a cell line derived from the ovary of the Chinese hamster, grown in culture. They are often used in biological and medical research. Furthermore, when proteins are being expressed for the purposes of therapeutic development, CHO tends to be the cell line of choice, as approximately 70% of licensed biotherapeutic proteins are produced in stably transfected CHO cells.

Figure 1. CHO cells grown in culture.