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A GPC3-targeting Bispecific Antibody, GPC3-S-Fab, with Potent Cytotoxicity
Published on: July 12, 2018
Fully human antibody VH domains to generate mono and bispecific CAR to target solid tumors
Guanmeng Wang1, Xin Zhou1, Giovanni Fucà1
1Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA.
Background:
Chimeric antigen receptor (CAR) T cells are effective in B-cell malignancies. However, heterogeneous antigen expression and antigen loss remain important limitations of targeted immunotherapy in solid tumors. Therefore, targeting multiple tumor-associated antigens simultaneously is expected to improve the outcome of CAR-T cell therapies. Due to the instability of single-chain variable fragments, it remains challenging to develop the simultaneous targeting of multiple antigens using traditional single-chain fragment variable (scFv)-based CARs.
Methods:
We used Humabody VH domains derived from a transgenic mouse to obtain fully human prostate-specific membrane antigen (PSMA) VH and mesothelin (MSLN) VH sequences and redirect T cell with VH based-CAR. The antitumor activity and mode of action of PSMA VH and MSLN VH were evaluated in vitro and in vivo compared with the traditional scFv-based CARs.
Results:
Human VH domain-based CAR targeting PSMA and MSLN are stable and functional both in vitro and in vivo. VH modules in the bispecific format are capable of binding their specific target with similar affinity as their monovalent counterparts. Bispecific CARs generated by joining two human antibody VH domains can prevent tumor escape in tumor with heterogeneous antigen expression.
Conclusions:
Fully human antibody VH domains can be used to generate functional CAR molecules, and redirected T cells elicit antitumoral responses in solid tumors at least as well as conventional scFv-based CARs. In addition, VH domains can be used to generate bispecific CAR-T cells to simultaneously target two different antigens expressed by tumor cells, and therefore, achieve better tumor control in solid tumors.
Insights
New VH domain-based chimeric antigen receptor (CAR) T cells effectively target multiple antigens in solid tumors. This approach overcomes limitations of traditional CARs, improving tumor control and offering a promising immunotherapy advancement.
Area of Science:
- Immunology
- Oncology
- Biotechnology
Background:
- Chimeric antigen receptor (CAR) T cells show efficacy in B-cell cancers but face challenges in solid tumors due to heterogeneous antigen expression and antigen loss.
- Targeting multiple tumor-associated antigens simultaneously is a strategy to enhance CAR T-cell therapy outcomes in solid tumors.
- Developing multi-antigen targeting CARs is difficult due to the instability of traditional single-chain variable fragments (scFvs).
Purpose of the Study:
- To evaluate the efficacy of VH domain-based CAR T cells targeting prostate-specific membrane antigen (PSMA) and mesothelin (MSLN) in solid tumors.
- To compare the antitumor activity and mechanism of action of VH-based CARs with traditional scFv-based CARs.
- To assess the stability and functionality of bispecific VH domain-based CARs for simultaneous multi-antigen targeting.
Main Methods:
- Generated fully human VH domains targeting PSMA and MSLN from a transgenic mouse.
- Constructed VH-based CARs and evaluated their antitumor activity in vitro and in vivo.
- Compared the performance of VH-based CARs with conventional scFv-based CARs.
Main Results:
- Human VH domain-based CARs targeting PSMA and MSLN demonstrated stability and functionality in vitro and in vivo.
- Bispecific VH-based CARs maintained target-binding affinity comparable to monovalent counterparts.
- Bispecific CARs utilizing VH domains effectively prevented tumor escape in models with heterogeneous antigen expression.
Conclusions:
- Fully human VH domains can be engineered into functional CAR molecules, eliciting potent antitumoral responses in solid tumors.
- VH-based CAR T cells provide antitumor activity comparable to or exceeding conventional scFv-based CARs.
- Bispecific VH-based CARs offer a strategy for simultaneous dual-antigen targeting, leading to improved tumor control in solid tumors.
