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A novel multimeric sCD19-streptavidin fusion protein for functional detection and selective expansion of
Hui Lian1,2, Jinhong Jiang3, Yao Wang2
1The First People's Hospital of Linping District, Hangzhou, Zhejiang, China.
Background:
CARs are engineered receptors comprising an immunoglobulin single-chain variable fragment (scFv) that identifies and binds to the target antigen, a transmembrane domain, and an intracellular T-cell signaling domain. CD19 is a B lineage-specific transmembrane glycoprotein and is expressed in more than 95% of B-cell malignancies. Streptavidin (SA) is a homo-tetrameric protein derived from Streptomyces avidinii, which can bind four biotin molecules with an extremely high affinity at a Kd value of 10-15 M.
Aims:
The aim of the study is to generate a novel soluble multimeric fusion protein, sCD19-streptavidin (sCD19-SA) for functional detection and selective expansion of CD19-targeted CAR-T cells.
Methods:
The fusion proteins CD19-SA was expressed in CHO cells and purified by use of Ni-nitrilotriacetic acid agarose beads.
Results:
A novel fusion protein (sCD19-SA) was generated, consisting of the extracellular domain of human CD19 and the core region of SA, and could be used to functionally detect CD19-targeted CAR-T cells. Furthermore, this protein was demonstrated to form multimers to activate CAR-T cells to induce their selective expansion. Importantly, sCD19-SA-stimulated CD19-targeted CAR-T cells could improve antitumor effects in vivo.
Conclusions:
Our study has highlighted the potential of utilizing antigen-SA fusion proteins such as sCD19-SA for CAR-T therapy for the functional detection of CAR expression and selective expansion of CAR-T cells.
Insights
A novel fusion protein, soluble CD19-streptavidin (sCD19-SA), enables detection and expansion of CD19-targeted CAR-T cells. This sCD19-SA fusion protein enhances CAR-T cell antitumor effects in vivo.
Area of Science:
- Immunology
- Biotechnology
- Oncology
Background:
- Chimeric antigen receptors (CARs) are engineered T-cell receptors for targeted cancer therapy.
- CD19 is a specific B-cell target found in over 95% of B-cell malignancies.
- Streptavidin (SA) is a high-affinity protein binder.
Purpose of the Study:
- To create a soluble multimeric fusion protein, sCD19-SA.
- To enable functional detection of CD19-targeted CAR-T cells.
- To facilitate selective expansion of CD19-targeted CAR-T cells.
Main Methods:
- Expression of CD19-SA fusion protein in CHO cells.
- Purification using Ni-nitrilotriacetic acid agarose beads.
Main Results:
- Generation of a novel sCD19-SA fusion protein.
- Demonstration of sCD19-SA's ability to detect and multimerize for CAR-T cell activation and expansion.
- Improved in vivo antitumor effects of sCD19-SA-stimulated CAR-T cells.
Conclusions:
- sCD19-SA is a promising tool for CAR-T therapy.
- Potential for functional detection and selective expansion of CAR-T cells.
- Highlights the utility of antigen-SA fusion proteins in CAR-T cell applications.
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