Figure 2
From: A modified human ELISPOT assay to detect specific responses to primary tumor cell targets
Optimization of effector to target cell ratio for use in the tumor IFN-γ ELISPOT assay. Various concentrations of pre- (white columns) and postvaccine (grey columns) PBMC (1 × 105, 2 × 105 or 3 × 105 cells/well) were co-cultured with different concentrations of sCD40Lt activated autologous tumor cells (1 × 105, 2 × 105 or 3 × 105 cells/well) for 48 h in the ELISPOT assay. Cryoperserved PBMC were thawed and cultured overnight. Data for PBMC concentrations of 3 × 105 and 2 × 105 cells/well are not shown because the resulting spots were too numerous and/or diffuse to count accurately. Significantly (p < 0.01) more IFN-γ production by responding T cells was observed in post- compared to prevaccine PBMC samples regardless of the effector to target ratio. Moreover, significantly (p < 0.01) more tumor specific T cells were enumerated at the 100:200 effector to target ratio compared to the other ratios tested. Data is presented as average number of spots per well ± SD and is representative of four experiments with similar results.