Team:UConn/Description
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Our Project Inspiration and Description
Monoclonal antibody (MAb) production can be expensive and time-consuming because current production methods use specialized mammalian cells (hybridomas). Bacterial cells are cheaper to cultivate and faster growing, meaning recombinant monoclonal antibody (rMAb) production in these cells could be more cost-effective and time-efficient. UConn iGEM’s 2019 project aims to synthesize glycosylated IgG MAbs within a strain of E. coli, for potential use in therapeutics and research.
rMAbs have been produced previously - for instance, non-glycosylated rMAbs were efficiently synthesized in the E. coli cytoplasm by Robinson et. al in 2015.[1] This was a valuable step, but it is important for antibodies to be glycosylated for optimal in vivo stability and recognition by host cells.[2]
Glycosylation involves the post-translational addition of a glycan (sugar) to a protein chain and is important for proper protein folding and stability. For antibodies, glycosylation is especially important in ensuring longevity and recognition by certain immune host cells. This enzyme, called ApNGT, was used by Xu et. al for in vitro glycosylation.[3] If a similarly efficient rMAb glycosylation was achieved in vivo, the cost of antibody glycosylation could be significantly reduced.
The aim of the project is to create correctly folded, glycosylated IgG antibodies within the cytoplasm of the genetically engineered E. coli. This E. coli will express both heavy and light chains of the full immunoglobulin G (IgG) antibody, as well as a glycosylation enzyme, NGT, derived from A. pleuropneumoniae. To aid in protein folding, the chassis organism will be E. coli SHuffle, a strain that has an oxidizing cytoplasmic environment and chaperones to aid in folding.
Citations
1. Robinson, M. P., Ke, N., Lobstein, J., Peterson, C., Szkodny, A., Mansell, T. J., ... & Taron, C. H. (2015). Efficient expression of full-length antibodies in the cytoplasm of engineered bacteria. Nature communications, 6, 8072.
2. Raju, S. (2003). Glycosylation variations with expression systems. BioProcess International, 1, 44-53.
3. Xu, Y., Wu, Z., Zhang, P., Zhu, H., Zhu, H., Song, Q., ... & Cheng, J. (2017). A novel enzymatic method for synthesis of glycopeptides carrying natural eukaryotic N-glycans. Chemical Communications, 53(65), 9075-9077.