Binding of PDL241 to leukocytes. (A) PBMC subsets were labeled for immunofluorescence analysis on the basis of co-staining: CD3+ CD4+ and CD3 + CD8+ (T cells); CD3-CD56+ (NK cells) and CD3 + CD56+ (NKT cells); CD19+ (B cells) and CD14+ (monocytes); CD27 + CD38 + CD138+ (plasmablasts and plasma cells). Lineage negative cells were first gated and then separated into HLA-DR + CD11c + (mDC), HLA-DR + CD123+ (pDC) and HLA-DR-CD123+ (basophils). Data representative of 1 of 10 donors. (B) Immunofluorescence analysis of co-staining of PDL241 (green) with anti-CD3 (T cells), anti-CD20 (B cells) or VS38c Ab (plasma cells) in red on OCT embedded frozen tissues from normal human tonsil. Nuclei were counter-stained with DAPI (blue). Double stained cells appeared yellow. Ab, antibody; DAPI, 4′,6-diamidino-2-phenylindole; NK, natural killer; OCT, optimal cutting temperature; PBMC, peripheral blood mononuclear cells.