Cell sorting and Culture
Fluorescence-activated cell sorting (FACS) were used to purify CD27+IgD+ B cells, 10ml blood was collected from SLE patients and healthy controls, peripheral blood mononuclear cells (PBMCs) were isolated from fresh blood samples using Ficoll density-gradient centrifugation, and then were stained as described above. After that, the aimed cells were harvested into the collection solution (RPMI 1640 supplemented with 10% FBS and 2% antibiotics) using FACS Aria II flow cytometry sorter according to the manufacturer’s instructions. The purified cells were further analyzed after sorting, the purity of which was 95–99%.