Establishment of a humanized mouse model: technical insight and applications

Humanized mouse models have emerged as an important tool for cancer research. These models enable the grafting of human immune and cancer cells, allowing the study of the complex interaction between the immune system and cancer. The work presented in this thesis has been developed in the animal facility at the department of Surgery, Oncology and Gastroenterology of the University of Padova, housed at the “Istituto Oncologico Veneto'' (IOV-IRCCS). It describes the practical work done to establish a humanized mouse model based on the immunodeficient strain NOD scid gamma (NSG). This model has been subsequently used to perform studies aimed at the treatment of Graft-versus-Host-Disease (GvHD). The techniques used in this work include animal irradiation with gamma rays to create a suitable environment for the engraftment of human cells, intravenous injection of peripheral blood mononuclear cells (PBMCs) to reconstitute the human immune system, and the assessment of animal weight and general health status through the study. To evaluate the humanization rate and the composition of the engrafted human cells, blood samples were periodically collected by puncturing of the submandibular vein, stained with a cocktail of antibodies and analyzed by flow cytometry. The results demonstrated successful engraftment of human immune cells, with humanization rates and animal survival varying in accordance with gamma radiation exposure and the number of cells injected. The engrafted human immune cells were predominantly T cells, which is consistent with the expected reconstitution patterns following injection of the PBMCs. The knowledge obtained from this study was further employed to investigate innovative strategies for the management of GvHD, hopefully leading to an improvement in the prognosis of bone marrow transplantation in patients with hematologic malignancies.