B6-hPD-1/hCTLA4 Mouse

PD-1 and CTLA-4 are checkpoint receptors that critically modulate T cell immunity. The genes PDCD1 and CTLA4 encode PD-1 and CTLA-4 respectively, with CTLA4 expression largely restricted to T cells, while PDCD1 is evident in activated T cells, B cells, and myeloid populations ^[1]. These transmembrane proteins function as key negative regulators of T cell activation ^[2]. CTLA-4 primarily operates in lymphoid tissues during early immune responses to restrain T cell proliferation, whereas PD-1 predominantly acts in peripheral tissues during the effector phase to dampen T cell activity and limit immunopathology, particularly in chronically stimulated or ‘exhausted’ T cells ^[2-3]. Aberrant regulation of PD-1 and CTLA-4 is implicated in the pathogenesis of cancers, including melanoma, non-small cell lung cancer, and renal cell carcinoma, as well as chronic viral infections such as hepatitis B and C ^[1][4]. Clinically, monoclonal antibodies targeting CTLA-4 (e.g., ipilimumab) and PD-1 (e.g., nivolumab, pembrolizumab) are established immunotherapeutic agents that enhance anti-tumor responses. By blocking these negative signaling pathways, these monoclonal antibodies restore the anti-tumor activity of T cells, significantly enhancing anti-tumor responses ^[1-2]. These drug applications have not only improved the treatment outcomes for various cancers but also offer new strategies for the treatment of chronic viral infections.

B6-hPD-1/hCTLA4 mouse is a dual humanized model of PD1 and CTLA4 constructed by humanizing the mouse Pdcd1 gene based on the CTLA4 humanized mouse model (Catalog No. C001413), due to the fact that the mouse Pdcd1 gene and Ctla4 gene are on the same chromosome. These mice express human CTLA4 and PDCD1 genomic sequences under the control of mouse promoters. This model is capable of reproducing the human PD-1/CTLA4 signaling pathway and is a valuable tool for studying cancers and chronic viral infections. Furthermore, this model provides a powerful preclinical research platform for evaluating the efficacy and mechanism of therapeutic drugs targeting the PD-1/CTLA4 signaling pathway.