CHO cells, or Chinese Hamster Ovary cells, are a type of cell line commonly used in biological and medical research. They are derived from the ovaries of the Chinese hamster and are favored for their ability to grow rapidly and produce large quantities of proteins. This makes them particularly useful in the production of therapeutic proteins and monoclonal antibodies. These cells are also genetically manipulable, allowing scientists to modify them for specific research purposes. CHO cells have become a standard in the biotechnology industry, playing a crucial role in the development of vaccines and other biopharmaceuticals.