Abstract 5192: NCG-MHC-dKO mice: an excellent model for PBMC reconstitution and pharmacodynamic evaluation in the absence of GvHD

Abstract

Abstract Human immune cell reconstitution (PBMC or CD34+ hematopoietic stem cell; HSC) is commonly performed in immunodeficient mouse strains such as NCG, NSG, or NOG. The use of PBMC is preferred for multiple reasons, including faster engraftment, lower cost, and the presence of mature immune cell populations. Although there are donor-to-donor variations in GvHD occurrence, and specific donors can be screened, the symptoms of GvHD typically occur within 4 weeks. GvHD significantly limits the study window required to evaluate the efficacy of therapeutic agents, such as cancer immunotherapies. GvHD is an immune reaction triggered mainly by donor T cells identifying the mouse MHC class I and class II as foreign and attacking the host cells and organs. Deletion of β2m (NCG- β2m-KO) reduces the occurrence of GvHD; however, β2m is not only in the MHC class I subunit but also in the FcRn subunit, of which deletion shortens the half-life of IgG, making it unsuitable for IgG antibody agent evaluation. In addition, the deletion of MHC class I or class II alone results in an imbalanced CD4/CD8 ratio. To solve these problems, we developed the NCG-MHC-dKO mouse model by knocking out the H2K1, H2D1, and H2Ab1 genes. Compared with the existing NCG- β2m-KO or other β2m null mouse models, the NCG-MHC-dKO significantly prolonged survival, reduced GvHD occurrence, and did not affect the CD4/CD8 ratio when reconstituted with PBMC. Furthermore, treatment with anti-PD-L1 antibodies significantly inhibited MDA-MB-231 tumor cell growth in PBMC-reconstituted NCG-MHC-dKO mice, similar to NCG mice. Based on our preliminary data, the NCG-MHC-dKO mouse is a promising model for antibody and cell therapy agent evaluation, assessing treatment-related cytokine release syndrome, and evaluating long-term toxicities of cell therapies. Citation Format: Huiyi Wang, Jun Xing, Jialu Fan, Huanhuan Hou, Santi Suryani Chen, Zhiying Li, Mark Wade Moore, Jing Zhao, Xiang Gao, Cunxiang Ju. NCG-MHC-dKO mice: an excellent model for PBMC reconstitution and pharmacodynamic evaluation in the absence of GvHD. [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 5192.