Characteristics and significance of T lymphocyte subsets in peripheral blood of osteosarcoma mice

BACKGROUND: Osteosarcoma (OS) is the most common malignant bone tumor, which often has lung metastasis. The survival rate after tumor metastasis is very low. Treatments including the antitumor immunocompetence of innate immune cells are found favorable for OS tumor. However, as a major means of early tumor detection, there are still few studies on T cells in peripheral blood of OS patients. METHODS: OS cells were implanted into the femoral bone marrow cavity of C3H/HeN mice to construct OS model. The proportion of T lymphocyte subsets in peripheral blood of mice was detected by flow cytometry on the 14(th) and 21(st) days after modeling. RESULTS: Compared with sham operation group, on the 14(th) day after operation, the proportion of γδT cells and CD4(+) regulatory T cells (Tregs) showed significantly higher level while other subsets didn’t have obvious difference. On the 21(st) day after operation, the proportion of CD3(+) T cells, γδ T cells, CD4(+) Tregs and Tregs/Th17 ratio were obviously higher than that of sham operation group. Meanwhile, while CD4(+) T cells and CD8(+) T cells were lower, suggesting the happen of peripheral immunosuppression. Comparing the T lymphocytes subsets on the 14(th) and 21(st) day after modeling in the tumor group, it was found that CD3(+) T cells and CD4(+) Tregs on the 21(st) day after modeling were significantly higher than those on the 14(th) day while CD4(+) T cells, CD8(+) T cells decreased significantly, indicating the changes of T lymphocytes in peripheral blood of OS mice are related to tumor development. CONCLUSIONS: The formation and development of femoral OS is accompanied by the disorder of peripheral blood T lymphocyte subsets and peripheral immunosuppression.