Mixed lymphocyte reaction (MLR) assay
The two-way mouse mixed lymphocyte reaction was conducted as described
in our previous study(Diao et al., 2012). In brief, single-cell
suspensions of spleens from C57BL/6 and BALB/C were prepared as
foregoing mentioned. Each set of 2×105 cells were seed
into 96-wells plates in RPMI-1640 with 10% FBS and 50 μM
β-mercaptoethanol. Cells were incubated for 4 days with indicated
concentrations of PIP in the presence or absence of uridine (100 μM).
Cell proliferation was evaluated by MTT as described above and the
proliferation of BALB/C spleen cells alone was served as background.