Effect of myeloid-derived suppressor cells on B cell function in mice bearing breast cancer / 中国肿瘤生物治疗杂志

ABSTRACT

@# Objective: To investigate the effect of myeloid-derived suppressor cells (MDSCs) from mice bearing breast cancer on the function of normal B cells. Methods:ABABL/c mouse 4T1 breast cancer model was established. The spleen MDSCs of tumor-bearing mouse and normal mouse spleen B cells were sorted by magnetic beads, and the sorted MDSCs and B cells were co-incubated. Flow cytometry was used to test the effect of MDSCs on the expressions of B cell surface molecules, including PD-1, PD-L1, CTLA-4, CCR6, CD62L and MHCⅡ; ELISA assay was used to detect the secretion of IgA, IgM and IgG by B cells; BrdU kit was used to detect B cell proliferation; andAnnexin V/PI staining was used to detect B cell apoptosis. B cells in the co-culture system were again sorted by magnetic beads and were then co-cultured with T cells; BrdU kit was used to detect T cell proliferation, and Annexin V/PI was used to detect T cell apoptosis. Results: Compared with B cell control group, the expression of PD-L1 on B cells in B+MDSC group was increased (P<0.01), while the expressions of PD-1, CTLA-4, CCR6, CD62L and MHC Ⅱ were all decreased (all P<0.01); The IgA, IgM and IgG secreted by B cells were significantly increased (all P<0.01); the proliferation of B cells was increased (P<0.01) and the apoptosis was decreased (P<0.01). Compared with the T cell control group, the proliferation of T cells in the B+MDSC (15) +T group was significantly reduced (P<0.01); however, there was no significant difference in T cell apoptosis. Conclusion: MDSCs from breast cancer bearing mice promotes B cell proliferation and inhibits B cell apoptosis, and the MDSC-induced B cells can inhibit T cell proliferation.