Short communicationMyeloid-derived suppressor cells mediate immune suppression in spinal cord injury

•The percentages of CD8 + and CD4 + T cells from SCI mice decreased significantly.•MDSCs from SCI mice increased dramatically, and recover gradually to normal levels at day 28.•The expanding MDSCs in SCI mice suppress T cell proliferation and the suppression could be reversed by blocking the arginase.

Spinal cord injury (SCI) is characterized by the loss of motor and sensory functions in areas below the level of the lesion and numerous accompanying deficits. Previous studies have suggested that myeloid-derived suppressor cell (MDSC)-induced immune depression may play a pivotal role in the course of SCI. However, the concrete mechanism of these changes regarding immune suppression remains unknown. Here, we created an SCI mouse model to gain further evidence regarding the relationship between MDSCs following SCI and T lymphocyte suppression. We showed that in the SCI mouse model, the expanding MDSCs have the capacity to suppress T cell proliferation, and this suppression could be reversed by blocking the arginase.