Peptide-scFv antigen recognition domains effectively confer CAR T cell multiantigen specificity

Area of Science:

• Immunology
• Oncology
• Biotechnology

Background:

• Immune escape is a major challenge for chimeric antigen receptor (CAR) T-cell therapies in hematological malignancies like acute myeloid leukemia (AML).
• Targeting multiple antigens can potentially overcome tumor heterogeneity and prevent immune escape.

Purpose of the Study:

• To develop and validate a bispecific CAR T-cell strategy targeting both GRP78 and CD123 antigens for enhanced efficacy in AML.
• To investigate the impact of linker variations on the functionality of peptide-scFv bispecific CARs.

Main Methods:

• Constructed a bispecific CAR T-cell construct (78.123) by combining a GRP78-specific peptide and a CD123-specific scFv using various linkers.
• Performed immunophenotypic and functional characterization of the bispecific CAR T-cells.
• Utilized protein structure prediction to analyze linker effects on CAR functionality.

Main Results:

• Bispecific CAR T-cells demonstrated successful recognition and killing of tumor cells expressing GRP78, CD123, or both.
• Improved antitumor activity was observed with bispecific CAR T-cells compared to monospecific counterparts when both antigens were present.
• Linker length and flexibility were identified as critical factors influencing bispecific CAR functionality.

Conclusions:

• A novel bispecific CAR design strategy targeting GRP78 and CD123 can effectively combat immune escape in AML.
• This approach offers a promising strategy to enhance CAR T-cell therapy efficacy against hematological malignancies.
• The peptide-scFv bispecific CAR design is adaptable for targeting other antigen combinations.