Nanobody-based CAR T cells targeting intracellular tumor antigens
Haixia Li, Dani Zhong, Huiguan Luo, Wei Shi, Shenxia Xie, Hangbiao Qiang, Li‐Chen Zhu, Li Gao, Jun Liu, Shuyang Sun, Ziqiang Ding, Xiaomei Yang, Xiaoling Lü
Abstract
Chimeric antigen receptor (CAR) T-cell immunotherapy has become one of the research hotspots in the treatment of malignant tumors nowadays. However, the available tumor surface antigens are limited in number. Most tumor-associated antigens are intracellular molecules that can't be targeted by conventional CAR T cells. As the major histocompatibility complex (MHC)/peptide complex is a presentation form of intracellular proteins on the surface of tumor cells, here, we chose the Glypican-3 (GPC3) oncoprotein and Wilms tumor 1 (WT1) oncoprotein as examples to explore whether nanobody (Nb)-based T cell receptor (TCR)-like CAR T cells could kill tumor cells by targeting the MHC/peptide complexes. Using the immune nanobody phage display library, we developed human leukocyte antigen (HLA)-A2/GPC3- and HLA-A2/WT1-specific nanobodies for the first time and then incorporated these nanobodies in two TCR-like CARs, targeting HLA-A2/GPC3 and HLA-A2/WT1 respectively. These TCR-like Nb CAR-redirected T cells could selectively recognize and lyse MHC/peptide complex-expressing tumor cells in vitro assays and subcutaneous mouse tumor models. This study offers a possible strategy for targeting intracellular antigens and widening the application of CAR T-cell therapy.