The relative mRNA and protein expression of HLA-DRB1 and HLA-DRB3.

a. The relative mRNA expression of HLA-DRB3*01 (n = 9), *02 (n = 16), and *03 (n = 11) in isolated B cells from deceased donors. The relative mRNA expression was determined by quantitative PCR (Q-PCR) and the values were normalized to reference gene HuPo. b. The cell surface expression of HLA-DRB3*01 (n = 7), *02 (n = 15), and *03 (n = 9) on B cells. Splenocytes from the donors were incubated with monoclonal 7.3.19.1 antibody, which binds to the specific epitope 77N that is present on HLA-DRB3*01, *02, and *03 (and HLA-DRB1*03). The B cells were gated using a fluorescently labelled CD19 antibody and the MFI values were corrected to MESF units using PE labelled beads. c. The relative mRNA expression of HLA-DRB1*03, *11, *13, and *14 and HLA-DRB3 in isolated B cells from deceased donors (n = 5 per group) determined by Q-PCR (normalized to HuPo). HLA-DRB1*01 was used as negative control for HLA-DRB1/3 primers. A primer for HLA-DRB1*12 was not included, therefore the products are not amplified. d, e. The expression of HLA-DRB3 on B cells with HLA-DRB1*03, *11, *12, *13, and *14 (n = 5 per group). HLA-DRB1*01 was used as negative control. The cell surface expression is shown as MESF units. The HLA-DRB1 typing is shown in S1 Table. Mann-Whitney t-test. The P values of <0.05 (*), <0.01 (**), and <0.001 (***) were significant.