Study on characteristics and immune mechanisms of CD11b+GR-1+ myeloid-derived suppressor cells in elderly mice / 中华老年医学杂志

ABSTRACT

Objective To study characteristics and immune mechanisms of CD11b+ GR-1-myeloid-derived suppressor cells (CD11b+ GR 1+ MDSCs) in elderly mice,as compared with those of healthy young mice.Methods Totally 20 healthy C57BL/6 young mice (aged 1-2 months) and 20 elderly mice (aged over 18 months) were randomly chosen and splenetic CD11b+ GR-1+ MDSCs were sorted with the MDSCs Isolation Kit.In vitro assays,the effects of young and elderly CD1 1b+ GR 1+ MDSCs on the proliferation of T cells were determined by Brdu Elisa.Transwell co-culture and real-timePCR were used to identify the mechanisms of different immune suppressive functions of CD11b+GR 1+ MDSCs sorted from young mice and elderly mice.Results Compared with young MDSCs,elderly MDSCs could evidently suppress the proliferation of T cells (t=8.67,P＜0.001),and this function could be reversed by trans-well co-culture (t=6.93,P＜0.001).The results of realtime PCR revealed that,compared with young MDSCs,elderly MDSCs expressed higher levels of arginase-1 (ARG-1),inducible nitric oxide synthase (iNOS),reactive oxygen species (ROS),interleukin 10 (IL-10),IL13 and transforming growth factor (TGF)-β (t=9.04,4.86,7.04,6.92,4.51,5.46,respectively,P＜0.05 or P＜0.01).Conclusions CD11b+GR-1+MDSCs sorted from healthy elderly mice can evidently suppress the proliferation of T cells through cell-cell contact and secretion of suppressive medium.