MDSC inhibiting proliferation of neuroblastoma antigen-specific CTL
The activated CTLs were stained by 5,6-carboxyfluorescein diacetate succinimidyl ester (CFSE) (final concentration of CFSE was 5 μmol/L14) and divided into two groups. In one group, CTLs were mixed with Gr-1+CD11b+MDSC (4:1) separated by MACS and stimulated proliferation by CD3/CD28 antibody. Meanwhile, in another group, all of the things was same except absence of MDSC. A parallel control group was set up for each group with the same method as the experimental group. After being cultivated for 4 days, the mixed cell system were observed by fluorescence microscopy and detected cell proliferation by flow cytometry.