{
  "abstract": "Background T-cell receptors (TCRs) and major histocompatibility complexes (MHCs) are critical targets in immunotherapy and cancer treatment. However, traditional E. coli expression systems face challenges like low yields and high endotoxin levels. The innovative T Cell Mate platform addresses these challenges by leveraging an ultra-high-titer CHO expression system to produce a range of T-cell-related proteins, including soluble TCRs (sTCRs), TCR-antibody fusions, and single-chain trimers (SCTs), consistently achieving high yield, high purity, and low endotoxin levels.Methods Codon-optimized DNA sequences were cloned into WuXi Biologics’ proprietary expression vector and transiently transfected into CHO cells using the WuXian Transient™ system. Cultures were harvested on Day 7, and the clarified supernatants were subjected to purification columns based on the expression titer. Depending on different constructs, proteins were purified using either Nickel column or Protein A chromatography, followed by SEC. Final products were characterized using SDS-PAGE, SEC-HPLC, Intact Mass analysis, and LAL assays.Results The T Cell Mate platform enabled high-titer, high-quality production across various T-cell-related proteins:STCRs: Following one-step affinity purification, the yields for one-arm Fc fusion, His-tagged TCR, and scFv-infused TCRs achieved 1092.0 mg/L, 112.2 mg/L, and 90.7 mg/L,SCTs: After two-step purification, the average yield of 10 SCTs reached 306 mg/L, indicating that the expression of SCTs in transient CHO surpassed that of RF-pMHC in coli. Additionally, a mouse SCT was successfully expressed in 20 mL CHO, achieving 10 mg yield with 99.57% purity and endotoxin levels <0.1 EU/mg.MHCII: Two zipper-fusion constructs achieved yields exceeding 500 mg/L with preserved structural integrity.MHCI in coli: A streamlined workflow enabled the production of over 300 RF-pMHCI complexes at scales ranging from 0.1 to 50 L, with validated complex integrity confirmed by LC-MS.Conclusions T Cell Mate sets a new standard for T-cell-related protein production. By combining ultra-high-titer CHO expression with flexible purification workflows, the platform consistently delivers high-yield, high-purity, and low-endotoxin proteins, such as sTCRs, TCR-Ab fusions, and SCTs, accelerating the discovery of T-cell-targeted therapeutics.",
  "authors": [
    {
      "affiliations": [
        "WXi Biologics, Shanghai, China"
      ],
      "name": "Dawei Zhang"
    },
    {
      "affiliations": [
        "WXi Biologics, Shanghai, China"
      ],
      "name": "Mengjie Lu"
    },
    {
      "affiliations": [
        "WXi Biologics, Shanghai, China"
      ],
      "name": "Zhengyang Zhao"
    },
    {
      "affiliations": [
        "WXi Biologics, Shanghai, China"
      ],
      "name": "Feng Li"
    },
    {
      "affiliations": [
        "WXi Biologics, Shanghai, China"
      ],
      "name": "Jiansheng Wu"
    }
  ],
  "title": "839 Innovative high-titer CHO platform to set new standard for T-cell-related protein production",
  "uid": "ad99562b-762e-506d-b5a2-69f27378865c"
}