The mammalian cell expression system utilizes mammalian cells as hosts for protein production. It possesses capabilities such as post-transcriptional modifications, proper protein folding, and assembly, enabling the expressed proteins to closely resemble their native states. This system serves as an excellent platform for expressing active protein factors and various receptor proteins.Protein production in mammalian expression systems typically employs two methods: transient transfection and stable transfection. Both approaches involve introducing the target gene into specific mammalian cells to express the desired protein. However, these methods differ in their underlying principles and operational procedures.

Operation steps：

1.The plasmids used for transient transfection and stable transfection differ significantly. Transient transfection plasmids do not require antibiotic resistance markers, whereas stable transfection plasmids must contain specific resistance genes to facilitate subsequent clonal selection. Additionally, the culture media and experimental reagents used for these two methods also vary.

2.Transient transfection procedures are simpler than establishing stable cell lines. For transient expression, the target protein can be obtained through steps including plasmid construction, cell thawing, transfection, cell culture, and protein purification. In contrast, establishing a stable cell line requires linearization of the constructed plasmid before introducing it into cultured mammalian cells. The plasmid must then integrate with the host genome through appropriate transfection methods, followed by multiple steps including pool selection, monoclonal screening, and cell passaging before obtaining a stably transfected cell line. Once established, these stable cell lines can continuously produce the target protein over an extended period.

Features：

KMD Bioscience specializes in providing mammalian recombinant protein expression services, utilizing advanced mammalian cell expression systems such as CHO and HEK293 cells to produce high-quality recombinant proteins for clients. Our services include gene codon optimization, vector construction, cell transfection, expression condition optimization, as well as protein extraction and purification. Through precise regulation of the expression system, we ensure that the recombinant proteins exhibit excellent biological activity and proper post-translational modifications, meeting the high standards required for scientific research, biopharmaceuticals, and industrial applications.With extensive project management experience and technical expertise, KMD Bioscience offers end-to-end services from concept to production. Whether it’s critical intermediates for drug development, experimental materials for disease research, or components for diagnostic reagent development, we provide customized solutions to accelerate project progress. By partnering with us, clients gain access to efficient and reliable mammalian recombinant protein expression services, driving their scientific research and product development forward.