Abstract 5828: Development of NK humanized mice models for the in vivo evaluation of NK cell-based therapeutics

With the recent advancements in anti-tumor immunotherapy, novel treatments have emerged and progressed rapidly. Several strategies are now being employed to enhance the efficacy of natural killer (NK) cells in tumor immunotherapy, including the use of monoclonal and multi-specific antibodies, as well as immune modulator molecules. Given these developments, there is an urgent need for the establishment of appropriate mouse models to effectively evaluate the therapeutic potential of these emerging immunotherapies. In this study, we developed a humanized mouse model for the specific reconstitution of functional and durable human NK cells within a murine system. In this model, human NK cells were purified from peripheral blood mononuclear cells (PBMCs) using magnetic bead separation, expanded in vitro, and subsequently engrafted into human IL-15 transgenic NOG mice. We collected blood samples from these mice to monitor human NK cell kinetics and profile using flow cytometry. The therapeutic efficacy of an anti-CD20 antibody was then evaluated in NK-humanized model using the SU-DHL-2 subcutaneous xenograft tumor model. Results indicated that anti-CD20 treatment was ineffective in non-NK-humanized mice. In contrast, in NK-humanized mice, human NK cells significantly inhibited tumor growth via antibody-dependent cellular cytotoxicity (ADCC). Additionally, we assessed NK cell intratumoral infiltration and the expression of activation markers at the end of the in vivo efficacy study, providing further insights into the immune response in the tumor microenvironment. In summary, we have developed a humanized mouse model capable of sustaining functional human NK cells for extended periods, ranging from weeks to months. This NK-humanized model provides a valuable preclinical platform for evaluating NK-modulating therapies and hold promise as a tool to accelerate the development of novel NK-based immunotherapeutics. Citation Format: Dong Wang, zhixiang zhang, zhongbao song, xiangnan qiang, qingyang gu. Development of NK humanized mice models for the in vivo evaluation of NK cell-based therapeutics [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2025; Part 1 (Regular Abstracts); 2025 Apr 25-30; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2025;85(8_Suppl_1):Abstract nr 5828.