Influence of Cyclical Administration with Low-dose Cyclophosphamide and Interleukin-2 on Regulatory T Cells of Murin Breast Cancer Model and Its Life Span

Objective To observe the influence of cyclical administration with Cyclophosphamide(CTX) and Interleukin-2(IL-2) on regulatory T cells(Treg) of murine breast cancer model and its life span.Methods Murine breast cancer model was established by inoculating s.c.mice with 4T1 breast cancer tumor cell line.Tumor-bearing BALB/c mice were randomly divided into four groups:IL-2 group and CTX group and IL-2+CTX group and control group.Mice in groups were injected intraperitoneally on schedule at the tenth day after tumor was established.Part of mice were sacrificed on day 4 after the last adminstration.We examined Regulatory T cells ratio of spleen cells by flow cytometry.Others were observed for survival.Results The CD4+CD25+/CD4+ ration in spleens of IL-2 group,CTX group,IL-2+CTX group and control group were 26.00%±0.98%,11.30%±0.85%,20.15%±1.11%,17.50%±1.13% respectively.Significant differences were observed between each group(P0.05).The longest life span in IL-2+CTX group and control group were 57 days and 46 days respectively,significant differences were observed between these groups.Conclusions Cyclical administration of low dose CTX keep Treg ratio which were expanded by IL-2 in a low level lead to a longer life span.