MDSC regulating the killing effect of neuroblastoma antigen-specific CTL in vitro
CTL, CTL+MDSC (1:4), and CTL+MDSC(1:4)+DOX(2µmol/L) were mixed with SK-N-SH cells and incubated respectively (CTL:SK-N-SH = 20:1). At the same time, blank control group, target cells group and effector cells group were set up. CCK-8 was added into the cell system (20 μl/hole) after incubation and absorbance value (A value) was detected in 450 nm wavelength by enzyme standard instrument. The cytotoxic activities of effector cells were evaluated by the killing rate. The killing rate of effector cells was calculated as follow, kill rate (%) = [A value of target cells group - (A value of experimental group - A value of effector cells group)]/A value of target cells group × 100%. The killing rates of CTLs to SK-N-SH cells between the groups were compared. The secretion levels of IL-2 and IFN-γ in the supernatant between the groups were detected and compared by enzyme-linked immunosorbent assay (ELISA).