Cell Line and Protein Expression

The application of recombinant proteins in scientific research has increased immensely. However recombinant protein production is a complex and unpredictable process. The expression of proteins in E. coli is the easiest, quickest and cheapest method. There are many expression vectors available with different N- and C-terminal tags and many different strains which are optimized for special applications.  Mammalian cells have great advantages over other host systems for the production of recombinant proteins. Both 293 and CHO cell lines are wildly used for preparative expression of more complex proteins, which also need proper post-translational modifications. Each cell line can be used for both transient and stable cell line expression.

StemImmune LLC provides a number of Protein Expression Services to meet your needs, StemImmune LLC combines both E.Coli and mammalian cell expression systems, ranging from expression of tagged proteins for research application to production of biopharmaceuticals for clinical use.

Protein expression service is a complete solution that spans from vector construction through to purification of ready to use proteins and can be tailored to meet your exact requirements.

Protein Expression in E. coli：

Protein expression in E. Coli includes: expression vectors construction, transformation, bacteria culture, expression induction and expressed analysis. Besides direct expression, Target proteins can also be expressed with different tags and/or fusion partners to increase protein stability and solubility. Following the expressions and purifications of the fusion protein, the fusion partners can be digested by site specific proteases and the target proteins are then produced. The fusion partners contain thioredoxin, GST, MBP, SUMO et al.

In our modified expression vector, target protein can be expressed E. Coli with Biotin acceptor peptide(BtAP) fused to the target protein. The BtAP can be biotinylated by biotin holoenzymesynthetase (BirA) expressed by host bacteria.The BtAP-fused target protein will be fully biotinylated in vivo .

Protein Expression in Mammalian Cells：

Stable expression in mammalian cells include: expression vectors construction, and transfection in appropriate cell lines. The transfected cells are cultured in selected mediums. Stable transfectants are isolated and expanded. Then the expressed proteins are analyzed by SDS-PAGE and /or Western blot. Proteins used for in vivo testing or cell culture that can be fused to albumin to improve half-life and bioavailability. In our modified expression vector, target protein can be expressed in mammalian cells with albumin fused to the N or C terminus to improve half-life and bioavailability.

Antibody Service

A reliable immunological assay demands reliable antibodies and antibody services. Our custom antibody production services range from: clone construction, protein expression, animal immunization, antiserum affinity purification, monoclonal antibody production, polyclonal antibody preparation, and immunoassay development.