The human B-LCL 7C3.DR4 was retrovirally transduced to express HLA-DR423 PLX4032 in vivo and cultured in IMDM supplemented with 5% heat inactivated calf serum. A B-LCL from a Danon disease patient (Danon B-LCL) [DR14(DRβ1*1401), DR15(DRβ1*1502)] was cultured in IMDM supplemented with 10% heat inactivated calf serum. In these cells, a 2-base-pair deletion in exon 3 of the LAMP-2 gene in the single X-chromosome-encoded copy disrupts LAMP-2 gene expression. Priess and 7C3.DR4 cells express endogenous immunoglobulin G (IgG) κ light chain while Frev and Danon
B-LCL are negative for κ light chain expression by Western blot analysis and instead, express IgG λ light chain. Danon B-LCL were transduced with DRβ1*0401 complementary DNA along with the mammalian selection marker histidinol using the retroviral cell line PA317hddw4c1 obtained from Dr William Kwok (Benaroya Research Institute at Virginia Mason, Seattle, WA). HLA-DR4+ Danon B-LCL clones (DB.DR4)
were selected by their growth in IMDM supplemented with 10% heat inactivated calf serum and 8 mm histidinol (Sigma-Aldrich, St Louis, MO). HLA-DR4 expression in the DB.DR4 transfectants was evaluated by flow cytometry using the HLA-DR4-specific antibody 3.5.9-13F10. The murine B-cell CH27 was retrovirally transduced with DRα and DR4β to express HLA-DR4 and cultured in Dulbecco’s modified Eagle’s minimal essential medium supplemented with 10% fetal bovine serum and 0·1%β-mercaptoethanol. Epigenetics inhibitor The T-cell hybridoma 17.9 is specific for the HSA64–76 epitope from human serum albumin (HSA).24 The T-cell hybridomas 2.18 and 1.21 are specific for the κI188–203 and κII145–159 epitopes from the Tideglusib human IgG κ light chain, respectively.25 The T-cell hybridoma 33.4 is specific for the HLA-A52–70 epitope from the α chain of HLA-A.26 All T-cell hybridomas were generated in the DR4(DRβ1*0401) transgenic mice27 and were cultured in RPMI-1640 supplemented with 10% fetal bovine serum, 0·1%β-mercaptoethanol, 50 U/ml penicillin, and 50 μg/ml streptomycin. Human GAD273–285 (IAFTSEHSHFSLK),
HSA64–76 (VKLVNEVTEFAKT), human IgG immunodominant κI188–203 (KHKVYACEVTHQGLSS), biotinylated κI188–203 (biotin-KHKVYACEVTHQGLSS), human IgG subdominant κII145–159 (KVQWKVDNALQSGNS) and human HLA-A52–70 (VDDTQFVRFDSDAASQRME) peptides were synthesized, purified to > 90% purity by reverse-phase high-performance liquid chromatography, and the sequences were confirmed by mass spectral analysis in conjunction with Quality Controlled Biochemicals (QCB; Hopkinton, MA). The HSA and human IgG antigens were purchased from Sigma-Aldrich. The mouse monoclonal antibodies (mAb) specific for either human LAMP-1 (H4A3) or human LAMP-2 (H4B4) were purchased from the Developmental Studies Hybridoma Bank (Iowa City, IA) for use in Western blots. The mouse mAb specific for human LAMP-1 and conjugated with AlexaFluor647 for use in immunofluorescence was purchased from eBioscience (San Diego, CA). The rat antibody 3.5.