CAMEL NANOBODY-BASED B7-H3 CAR-T CELLS WITH HIGH EFFICACY AGAINST SOLID TUMORS

Abstract Background and significance Chimeric antigen receptor (CAR)-T cell therapy shows promising potency for treating patients with hematological malignancies. However, follow-up data indicate that only 30% to 50% of these experience long-term disease control. In solid tumors, the B7-H3 transmembrane protein is an emerging target harbors in its ectodomain two distinct epitope motifs - IgC IgV. Here, we developed nanobody-based CAR-T strategy targeting investigated anti-tumor efficacy xenograft mouse models. Methods We isolated anti-B7-H3 VHHs from our large dromedary camel VHH nanobody libraries great diversity (> 1012 total) by phage display technology. The binding was validated ELISA, flow cytometry, Octet. A peptide library synthesized predict select VHHs. Anti-tumor effect cells determined via luciferase-based killing assay as well Two tumor models, human neuroblastoma pancreatic adenocarcinoma, were used present study. Single-cell transcriptome RNA sequencing coupled single T-cell functional proteomics analysis analyze functionality cells. Results analyzed isoforms at levels 4IgB7-H3 a therapeutic dominant isoform tumors. Targeting 4Ig isoform, obtained panel high-affinity nanobodies cross-reactive human, mouse, rat, monkey. Furthermore, demonstrated based on had potent antitumor activity against tumors rigorous T signaling significant infiltration. Mechanistically, uncovered top-upregulated genes might be critical persistence polyfunctional microenvironment. Conclusions Our results provide novel product use therapy.