A Humanized HLA-Matched Avatar Model for Preclinical Evaluation of DNA Cancer Vaccines

Building on seminal studies which utilized RAG2-deficient mice engrafted with human tumors and reconstituted with human PBMCs to investigate antitumor immunity, the field still lacks robust preclinical systems that faithfully recapitulate human HLA-restricted T cell responses. Here, we describe a humanized murine platform—the HLA-matched Immuno-avatar model—engineered to evaluate DNA-based cancer vaccines delivered by electroporation. The model is based on the adoptive transfer of splenocytes from immunocompetent, vaccinated HLA-A0201 transgenic (HHK) donors into immunodeficient RAG2−/− IL-2Rγ−/− recipients, which are subsequently xenografted with a human colon carcinoma cell line and treated with a DNA vaccine encoding HLA-restricted epitopes of carcinoembryonic antigen (CEA). Transfer of splenocytes from CEA-vaccinated donors induced a robust and statistically significant antitumor effect in recipient mice. This humanized, HLA-matched, and functionally immunocompetent platform provides a flexible and translationally relevant system for the preclinical evaluation of both off-the-shelf and personalized cancer vaccines targeting evolving tumor antigen repertoires.