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Transgenic TCR expression: comparison of single chain with full-length receptor constructs for T-cell function
Tong Zhang1, Xianghui He, Tom C Tsang
1Gene Therapy Group, Department of Microbiology and Immunology, University of Arizona, Tucson, Arizona 85721, USA.
Cancer Gene Therapy
|May 22, 2004
Summary
Engineered T cells using three-domain single-chain T-cell receptors (3D-scTCRs) show promise for adoptive immunotherapy. While functional, these 3D-scTCR T cells require higher antigen stimulation thresholds compared to traditional methods.
Area of Science:
- Immunology
- Cellular Therapy
- Molecular Engineering
Background:
- Adoptive immunotherapy utilizes T-cell receptor (TCR) gene-modified T lymphocytes.
- Full-length TCR (flTCR) modifications face challenges like chain mispairing and CD3 complex downregulation.
- Three-domain single-chain TCRs (3D-scTCRs) offer a potential solution by linking Valpha and Vbeta chains with signaling domains.
Purpose of the Study:
- To investigate the functional capacity and expression of 3D-scTCR-modified T cells.
- To evaluate the impact of transmembrane regions and signaling domain placement on scTCR surface expression.
- To compare the antigen sensitivity and activation requirements of scTCR-modified T cells against flTCR-modified T cells and native CTLs.
Main Methods:
- Retroviral transduction of T lymphocytes with 3D-scTCR constructs.
- Analysis of scTCR surface expression influenced by transmembrane region origin and signaling domain placement.
- Assessment of T cell functionality via cytokine release (IL-2, IFN-gamma) and cytolytic activity.
- Evaluation of co-stimulatory molecule (CD8, CD28) and CD3 complex effects on T cell activation.
- Determination of antigen stimulation thresholds for scTCR-modified T cells.
Main Results:
- scTCR surface expression is modulated by the transmembrane region's origin and signaling domain configuration.
- scTCR-modified T cells demonstrate antigen-specific cytokine release and cytolytic activity.
- CD8 and CD28 co-stimulation enhance scTCR-mediated T cell activation, unlike the complete CD3 complex.
- scTCR-modified T cells exhibit reduced sensitivity, requiring higher antigen stimulation levels (approx. 10^-8 M peptide) compared to flTCR T cells and native CTLs.
Conclusions:
- 3D-scTCRs are functional in modified T cells, exhibiting cytokine release and cytolytic potential.
- Optimizing transmembrane regions and signaling domains is crucial for efficient scTCR surface expression.
- While requiring higher antigen thresholds, scTCRs offer a viable platform for adoptive immunotherapy development.
- Further research is needed to enhance scTCR efficiency for effective in vivo therapeutic applications.