Comparison of cell-ELISA and microproliferation. Four healthy donors were tested with the two assays in miniaturized formats (384- well plates, open bars, and 1,536-well plates, gray bars). Cell-ELISA results are comparable in the two formats since they refer to IFN-γ concentrations in culture conditions in which PBMC are at the same density. On the contrary, microproliferation results shown for 384-well plates were divided by 5 to show proliferation of 10 × 103 PBMC for comparison with results obtained in 1,536-well plates. This correction showed that the two formats provide similar results, with a consistent, but not significant, trend for higher efficiency of the 1,536-well format than of the 384-well format.