ObjectiveTo explore the dynamic changes of immune cell populations in Panc02 pancreatic cancer bearing immunocompetent mice. MethodsThe C57BL6/J mice syngeneic pancreatic cancer cell line Panc02 were subcutaneously implanted to establish the immunocompetent murine pancreatic cancer bearing model.According to the tumor size, the tumor was classified into 4 stages, named T1-T4, respectively.The flow cytometry was performed to identify the dynamic changes of different cell populations, such as inflammatory cells (CD45+), T helper (Th) lymphocytes, cytotoxic T lymphocytes (CTL), B lymphocytes, granulocytes, macrophages, dendritic cells (DC), natural killer (NK) cells, and natural killer T (NKT) cells in the peripheral blood and tumor tissue. ResultsThree dynamic types of immune cells with the tumor progression were identified:consistent increase, consistent decrease, increase and then decrease.①In peripheral blood:The proportion of the Th lymphocytes, CTL, and B lymphocytes consistently decreased; The proportion of granulocytes consistently increased; The proportion of the DC, macrophages, NK cells, and NKT cells increased from T1 to T3 stage but sharply decreased at T4 stage.②In tumor tissue:The intratumoral CD45+ cells consis-tently increased; The proportion of the granucolyte, macrophages, and DC consistently increased; The proportion of the Th lymphocytes and the CTL consistently decreased; The proportion of the B lymphocytes did not change significantly; The proportion of the NK cells or NKT cells increased from T1 to T3 stage but sharply decreased at T4 stage. ConclusionWith pancreatic cancer progression, the immune cell populations show different dynamic change models, which imply their important roles in predicting the prognosis and the integrated treatments of pancreatic cancer.