MUTZ-3 possesses functional antigen processing and presentation pathways.

(A) MHC class I presentation. MUTZ-3 iDCs stimulate flu-specific cytotoxic T lymphocyte (CTL) responses by presentation of HLA-A2.1–restricted flu peptides. (Ai) MUTZ-3 DCs were loaded with the HLA-A2.1 binding peptide derived from the haeminfluenza matrix protein (M1_58-66) and cocultured with CD8⁺ T cells. The production of IFN-γ by CTLs (effector cell concentrations ranging from 0.5 × 10⁵ to 0.125 × 10⁵ per well) cocultured with M1 flu peptide–loaded (■) or HPV 16 E7–derived peptide-loaded T2 cells (□) as target cells (0.1 × 10⁵per well) is shown. (Aii) Alternatively, MUTZ-3 DCs were infected with a recombinant adenovirus containing the M1 matrix protein gene and cocultured as described. CTLs were then restimulated overnight with M1 flu peptide–loaded (●) or HPV 16 E7–derived peptide-loaded T2 cells (○). Data are from one experiment representative of 3. (B) MHC class II antigen presentation. MUTZ-3 mDCs process and present the peptides derived from the common recall antigen TT, and stimulate TT-specific CD4⁺ T cells. Data are from one experiment representative of 3. (C) Presentation of alpha-GalCer via CD1d. MUTZ-3 iDCs were loaded with alpha-GalCer or vehicle control (dimethyl sulfoxide [DMSO]) and cultured in the absence or presence of TNFα hi for 48 hours. mDCs were then cocultured for 9 days with NKT cells isolated from healthy donors in the presence of IL-7 (10 ng/ mL) and IL-15 (10 ng/mL) and with or without CD1d51 blocking antibody. Results show the relative yield of NKT cells in vehicle and alpha-GalCer–loaded MUTZ-3 iDCs and mDCs with or without blocking of alpha-GalCer presentation using an anti–CD1d blocking antibody. Data are from one experiment representative of 3.