Mammalian systems like Chinese hamster ovary (CHO) or HEK cell lines are able to correctly produce recombinant protein modifications. These systems are genetically more stable and accepted by regulatory bodies.
Transfection may be stable (foreign DNA integrate to the host DNA) or transient (genetic altercation is not permanent).
In transient transfection, the transfected DNA is not incorporated in the host’s genome. The host processes the foreign DNA which will then cause phenotypic changes. Cells are usually harvested
On the other hand, stable transfection involves integration to the host’s chromosomal DNA. The transfected DNA is carried to progeny, thus, the stable cell line is generated. Screening and selection is involved in generating stable cell lines to find the best one in producing the recombinant protein.