Decreased CD4⁺ T-cell proliferation by antibody blocking of MHC class II. mIg-loaded DCs were preincubated with anti–HLA-DR or isotype control antibodies prior to coculturing with CFSE-labeled PBMCs, as in Figure 2. For each patient (n = 9), the percentage inhibition of the CD4⁺ T-cell proliferation by blocking (▩) or isotype control antibodies (□) are presented (example of FACS analysis in Figure 1). In the case of patient nos. 2, 4, and 8, the control antibody increased the percentage of proliferating cells marginally, resulting in negative values.