This study optimizes CD30 CAR design by introducing 4-1BB and OX40-derived spacers, effectively reducing Fc receptor-related off-target activation and cytokine release while maintaining anti-tumor activity. It provides a novel structural engineering strategy to improve CAR-T cell therapy for CD30-positive hematologic malignancies.
Literature Overview
The article '4-1BB and OX40-Derived Spacers Enhance CD30 CAR Activity and Safety in CD30-Positive Lymphoma Models' published in Molecular Therapy reviews and summarizes the impact of different spacer domains on CAR-T cell function, persistence, and safety in CD30-targeted immunotherapy. By optimizing spacer design, this study significantly reduces non-specific interactions between CAR-T cells and myeloid cells, enhances tumor infiltration in vivo, and decreases inflammatory cytokine release, offering structural insights for clinical development.
Background Knowledge
CD30 is an immune receptor highly expressed in multiple hematologic malignancies, including classical Hodgkin lymphoma (cHL) and T-cell lymphomas. Currently, CD30 CAR-T cells based on the murine HRS-3 antibody demonstrate acceptable safety and preliminary efficacy in clinical trials but suffer from poor persistence, leading to low one-year progression-free survival rates. The hinge/spacer domain in CAR structure critically influences antigen recognition distance and immunological synapse formation, with its origin directly affecting functional stability. Wild-type IgG1 spacers induce non-specific activation via Fc receptor binding, increasing cytokine release and reducing in vivo persistence. This study identifies the HRS-3 antibody's binding epitope on CD30 and introduces novel spacers to explore structural and functional optimizations, addressing limitations in existing CAR designs.
Research Methods and Experiments
Researchers first mapped the HRS-3 antibody's binding epitope on CD30 using phage display screening, identifying CRD5 as the primary interaction domain. Subsequently, spacers derived from distinct immune receptors (OX40, 4-1BB, CD44, CD96) were designed and tested. Functional assessments included cytokine release, cytotoxicity, T-cell expansion, and persistence in both in vitro and in vivo lymphoma models.
Key Conclusions and Perspectives
Research Significance and Prospects
This work establishes structural optimization principles for CD30-targeted CAR-T therapy. The 4-1BB and OX40 spacers enhance functional stability while mitigating Fc receptor-associated systemic toxicity. Future applications may extend this strategy to other IgG1-based CAR designs, improving therapeutic indices across hematologic and solid tumors. The integration of humanized scFvs with optimized spacers could reduce immunogenicity and expand clinical applicability, offering safer CAR structures for personalized immunotherapy.
Conclusion
In summary, this study clarifies the HRS-3 antibody's binding site on CD30 through structural analysis and functional validation. By developing CAR constructs incorporating 4-1BB and OX40-derived spacers, the research demonstrates reduced Fc receptor-associated non-specific activation and cytokine release while preserving potent anti-tumor activity. The combination of humanized HRS-3 scFv with 4-1BB spacers achieves efficient tumor targeting without off-target toxicity, providing an optimized T-cell engineering framework for CD30-positive lymphoma immunotherapy. These findings establish foundational insights for clinical translation in CD30+ hematologic cancers and introduce innovative perspectives on spacer domain engineering in immunotherapy.
