|dc.description.abstract||Introduction: Myeloid-derived suppressor cells (MDSCs) are a heterogeneous population of immature myeloid cells that can suppress the adaptive and innate immune responses and upregulate other downregulatory elements of the immune system. MDSCs may help to suppress graft-versus-host disease (GVHD) in allogeneic transplant recipients. GVHD is a complication following allogeneic stem cell transplantation in which graft T cells launch an immunological response against recipient tissues.
Objective: We wished to identify a growth factor (GF) that promoted and expanded a suppressive MDSC population.
Methods: To test the ability of myeloid GFs to maintain, expand and improve suppressive function of bone marrow (BM)-derived MDSCs we cultured murine BM with G-CSF, GM- CSF or M-CSF. Cells were stained with fluorescent antibodies to surface antigens that are expressed by MDSCs and measured by flow cytometry. Suppressive function of in vitro GF-treated BM was measured by inhibition of third party CFSE-labeled splenocyte proliferation. The effects of blocking MDSC suppressive function by adding inhibitors were evaluated. Comparisons were made between GF treatment groups using one-way ANOVA tests and two-way ANOVA tests with Tukey’s range tests.
Results: 4 days of culture of BM with 10 ng/ml GM-CSF, 20 ng/ml G-CSF or 20 ng/ml M-CSF generated high numbers of live MDSC, of which GM-CSF stimulation generated the highest number. MDSCs induced by different GF can suppress the proliferation of CD4+ T lymphocytes in dose-dependent manner, of which M-CSF- treated murine BM showed greatest suppressive function (suppression rates for 1:1 co-culture are G-CSF 12%[SD=4], GM-CSF 72.9%[0.5], M-CSF 83%, no GF 24%; adjusted P values < 0.0001 for all comparisons except P=0.0104 G-CSF vs. no GF and P=0.02 for GM-CSF vs. M- CSF using 2-way ANOVA). M-CSF-treated BM promoted the greatest regulatory T cell expansion in co-culture. Addition of an iNOS inhibitor, not the inhibitors to M-CSF-treated BM and splenocyte co-culture appeared to reverse the suppressive function of this cell population.
Conclusion: M-CSF-induced MDSCs, as well as GM-CSF-induced MDSCs, had a strong suppressive effect on the proliferation of murine splenocytes, and may through an iNOS pathway. The use of M-CSF in the post-transplant setting may be a new tool for the treatment of GVHD.||en_US
|dc.description.sponsorship||H.T. Thorlakson Foundation
Dean, Faculty of Medicine
Manitoba Health Research Council
Manitoba Institute of Child Health
Kidney Foundation of Manitoba
Leukemia and Lymphoma Society of
Manitoba Medical Service Foundation
Associate Dean (Research), Faculty of
Heart and Stroke Foundation
Health Sciences Centre Research
|dc.subject||Myeloid-derived suppressor cells (MDSCs)||en_US
|dc.subject||graft-versus-host disease (GVHD)||en_US
|dc.title||In vitro effects of G-CSF, GM-CSF, and M-CSF treatments on expansion and suppressive function of murine bone marrow-derived myeloid-derived suppressor cells||en_US