A Lung-Immune Dual-Humanized Mouse Using Cryopreserved Tissue Enables Infection and Immune Profiling of Human Common Cold Coronaviruses.

Human common cold coronaviruses (CCCoVs, e.g., 229E, NL63, OC43, HKU1) hold critical yet underexplored significance in understanding coronavirus evolutionary dynamics and immune cross-protection, offering insights for predicting emerging pathogens and developing pan-coronavirus vaccines. However, research is hindered by the lack of animal models due to strict human-specific tropism and the confounding effects of frequent co-infections from clinical samples, which obscure virus-specific pathogenesis. Although lung-humanized mice have been used in SARS-CoV-2 studies, their application to CCCoVs remains unvalidated and relies on logistically challenging fresh human tissues. This study optimizes a transplantation strategy using cryopreserved human fetal lung tissue, achieving enhanced engraftment efficiency. And the refined model supports robust infection by all four major CCCoVs and demonstrates the therapeutic efficacy of Paxlovid against HKU1. Furthermore, comparative analysis reveals phenotypic distinctions in human immune cells between native mouse lungs and human lung implants in lung-immune dual-humanized mice. The model also enables validation of virus-specific T cell responses and assessment of SARS-CoV-2 cross-reactivity post-HKU1 infection. Overall, this study establishes a scalable platform using cryopreserved tissues for respiratory virus research, overcoming prior limitations in modeling human-specific tropism and dissecting immune-pathogen interactions.