Changes in CD4+CD25+Foxp3+ Regulatory T Cells in Relation to Aging and Lung Tumor Incidence

SummaryBackgroundCD4+CD25+Foxp3+ regulatory T (Treg) cells mediate immunosuppression and play an important role in tumor immune evasion. Studies have demonstrated that this cell population represents an aging-related change. It is not clear whether this change leads to higher tumor incidence in the elderly. We investigated changes in CD4+CD25+Foxp3+ Treg cells in relation to aging and tumor incidence.MethodsWe set up a Lewis lung cancer model with 26 C57BL/6 female mice. The animals were divided into six groups: young healthy, middle-aged healthy, elderly healthy, young tumor, middle-aged tumor and elderly tumor. We evaluated changes in CD4+CD25+Foxp3+Treg cells in the spleen of all animals using a flow cytometry method. Levels of Foxp3 m RNA in splenocytes were measured using a real-time RT-PCR method.ResultsThe CD4+CD25+Foxp3+/CD4+ T cell ratio (t = 2.23, p = 0.032) and Foxp3 mRNA levels (t = 3.26, p = 0.0042) were higher in the tumor groups than in the healthy groups. In the healthy groups, there was a significant increase in CD4+CD25+Foxp3+ Treg cells on aging (F = 47.70, p = 0.000); elderly mice had a significantly greater population of CD4+CD25+Foxp3+ Treg cells in spleen compared to the younger groups. The highest population was observed in the elderly tumor group. The same trend was evident for Foxp3 mRNA (F = 6.56, p = 0.0090).ConclusionsThe results suggest a close relationship between changes in CD4+CD25+Foxp3+ Treg cells and aging and lung tumor genesis and development.