Citation
- Authors: Yang R. et al.
- Year: 2023
- Journal: Biochem Biophys Res Commun 644 1-7
- Applications: in vitro / DNA / FectoPRO
- Cell type: CHO-S
Description: Chinese hamster ovary cells
Method
The bsAbs were generated similarly to previous studies [15,16]. Briefly, three expression plasmids were synthesized and sequencing verified by AuGCT Biotech (Wuhan). Then these expression vectors were transfected into CHO-S cells (cGMP Banked) (Invitrogen) using the Fecto PRO Reagent (Ployplus) according to the manufacturer's protocol. After a week, the cell culture supernatant was collected and serially purified by Sepharose Fast Flow protein A affinity chromatography column (GE), Fab Affinity KBP Agarose High Flow Resin (ACROBio systems), and SP cation exchanged chromatography column (GE). Finally, purified proteins were analyzed by size-exclusion chromatograms. The alternative bsAb control molecule, Vα7.2 x Null, targeting Vα7.2 and fluorescein (derived from Clone 4-4-20 [17]), and two parental monoclonal antibodies, including Vα7.2 mAb and PD-L1 mAb, were similarly prepared.
Abstract
Pan-T cell targeting by CD3-based T cell engagers has brought program-shift treatment and management of blood tumors. However, these modalities have been shown to provoke all types of T cells leading to cytokine storm syndrome, and activate Treg cells. Thus, modulating and potentiating the antitumor responses of a specific T cell subset was encouraged. We initially found that high purity of mucosa-associated invariant T (MAIT) cells could be expanded by the combination of plate-immobilized Vα7.2 mAb (Clone 3C10) and IL2 plus IL15. Then, we generated a novel anti-Vα7.2 TCR bsAb, Vα7.2 x PD-L1, to invoke the anti-tumor potency of these expanded MAIT cells. Furthermore, our data have demonstrated that Vα7.2 x PD-L1 could mediate the cell-to-cell conjunction between MAIT cell and tumor cell line, selectively elicit the activation, cytokine production, degranulation, and cytotoxicity of the expanded MAIT cells in the presence of target cell only. Collectively, this proof-of-concept study provides a new tool to explore the clinical potential of MAIT cells in fighting against PD-L1 positive solid tumors and suggests additional encouragement in designing novel T cell engagers targeting TCR alpha chain specific innate-like T cells subsets, other than pan CD3+ T cells.