Preliminary Study On Labeling The Regulatory T Cells Of Mice With Ultrasmall Superparamagnetic Iron Oxide Ex Vivo

Objective To label the regulatory T cells with ultrasmall superparamagnetic ironoxide (USPIO) and evaluate the biological effects of USPIO on the regulatory T cellsin vitro.Methods The regulatory T cells were isolated from the spleen of mice withEasySep Mouse CD4+T cell pre-enrichment kit and CD25Selection kit. Collectedthe lymphocytes from the mouse spleen then incubated with USPIO for3h to24h atthe iron concentration of0.01,0.05,0.10and0.15mg/ml. Cells incubated withoutUSPIO served as the control. The uptake capability of USPIO was evaluated byPerussian blue staining and measured quantitatively with atomic absorptionspectrometry. The cell activity was monitored by MTT method. Chose the rightconcentration of the USPIO and incubated with the regulatory T cells isolated fromthe mice spleen using Mouse CD4+CD25+T cell Easysep kits. The suppressiveeffect of the regulatory T cells on the proliferation of CD4+T cells was analyzed inproliferation assays. The expressing of Foxp3of the regulatory T cells was detectedby Flow Cytometry.Results DMSA coated USPIO was uptaken by the regulatory T cells in aconcentration-dependent manner. Within a certain range of the concentration, USPIOhad no obvious effects on the activity, phenotype and suppressive function of theregulatory T cells. The MR images resulting from USPIO labeled cells showed thatthe MR signal in T2weighted images significant decreased.Conclusion The regulatory T cells were successfully labeled with USPIOin vitro. In a certain range of concentration, USPIO have no effects on the activity andfunction of regulatory T cells.