The Importance of Myeloid-Derived Suppressor Cells in the Regulation of Immunosuppressive Mechanisms by Severe Fever with Thrombocytopenia Syndrome

Liping Sun

doi:10.11648/j.ejcbs.20180405.11

Abstract

Objective: Severe fever with thrombocytopenia syndrome (SFTS) is an emerging infectious disease caused by SFTS virus (SFTSV) with a high fatality rate. The objective of our study was to assess the mechanisms of immunofunction through detecting the presence of myeloid-derived suppressor cells (MDSC), granulocyte-colony stimulating factor (G-CFS) and T cells in SFTS patients. Methods: Serum samples from 30 SFTS cases and 20 healthy donors were collected for the test with flow cytometry and sandwich ELISA which contains CD3+, CD4+ T lymphocytes, subsets of MDSC and G-CSF. Results: Granulocytic MDSC (G-MDSC) and monocytic MDSC (M-MDSC) were significantly elevated in SFTS compared to normal control, and G-CSF was expressed at increased frequency. In contrast, CD3+ and CD4+ T lymphocytes were significantly diminished. Further analysis revealed that G-MDSC and G-CSF were higher in severe SFTS infection compared to the patients in mild SFTS infection, and the numbers of CD3+ and CD4+ T lymphocytes showed a more robust pattern of depression. Conclution: In summary, we have characterized an immunosuppressive mechanism in SFTSV infection dependent on G-CSF induction on MDSC and MDSC suppressing T cells.

Highlights

Myeloid-derived suppressor cells (MDSC) are a group of phenotypically heterogeneous myeloid cells that expands during cancer, inflammation and infection, and that plays a remarkable role in suppressing T-cell responses [1]
Our results demonstrate that both monocytic MDSC (M-MDSC) and granulocytic MDSC (G-MDSC) increase in Severe fever with thrombocytopenia syndrome (SFTS) patients and are significant (p < 0.05)
In this article we focused on the mechanism of immune suppression and provided opportunities to better understand the immune responses for SFTS patients

Summary

Introduction

Myeloid-derived suppressor cells (MDSC) are a group of phenotypically heterogeneous myeloid cells that expands during cancer, inflammation and infection, and that plays a remarkable role in suppressing T-cell responses [1]. MDSC were defined as cells that co-purified with mononuclear cells and granulocyte markers [2]. Different subsets of MDSC might use different mechanisms to suppress T-cell proliferation. Both populations suppressed antigen-specific T-cell proliferation to an equal extent, by using distinct effector molecules and signal pathways [4]. Features common to all MDSC are their myeloid origin, immature state, biological activity and a remarkable ability to suppress T-cell responses. Many underlying mechanisms of MDSC activity and their specific

Methods

Results

Conclusion