Processing and presentation of HLA class I and II epitopes by dendritic cells after transfection with in vitro-transcribed MUC1 RNA.
RNA transfection of dendritic cells (DCs) was shown to be highly efficient in eliciting CD8+ and CD4+ T-cell responses. However, antigen presentation pathways involved in generation of human leukocyte antigen (HLA) class I and class II peptides have remained elusive. To analyze this we incubated mucin 1 (MUC1) RNA-transfected DCs with compounds known to inhibit HLA class I presentation and used these cells in chromium 51 (51Cr)-release assays. As effectors, we used cytotoxic T lymphocyte (CTL) lines specific for the MUC1 peptides M1.1 and M1.2. We observed that the presentation of HLA-A*02 epitopes is inhibited by brefeldin A and lactacystin. To determine the requirement of a functional transporter associated with antigen processing (TAP), we cotransfected DCs with MUC1 and infected cell peptide 47 (ICP47) RNA. ICP47 could only inhibit the presentation of the M1.1 but not the M1.2 peptide, indicating that this epitope derived from the signal sequence is presented independently of TAP. Cocultivation of MUC1 RNA-transfected DCs with MUC1-specific CD4+ T lymphocytes revealed that the presentation of HLA class II peptides is sensitive to proteasomal inhibitors and brefeldin A. Furthermore, the presentation pathway requires lysosomal and endosomal processing and is mediated by autophagy. Our results demonstrate that the efficient presentation of cytosolic proteins on major histocompatibility complex (MHC) class II combines the proteolytic and lysosomal pathways.
Dörfel
Daniela
D
Department of Hematology, Oncology and Immunology, University of Tübingen, Tübingen, Germany.
Appel
Silke
S
Grünebach
Frank
F
Weck
Markus M
MM
Müller
Martin R
MR
Heine
Annkristin
A
Brossart
Peter
P
D017951:Antigen Presentation / Q000502:physiology*; D001343:Autophagy / Q000276:immunology; D003600:Cytosol / Q000276:immunology; D003713:Dendritic Cells / Q000276:immunology*; D018274:Electroporation; D011992:Endosomes / Q000276:immunology; D000939:Epitopes / Q000276:immunology; D015395:Histocompatibility Antigens Class I / Q000276:immunology*; D000949:Histocompatibility Antigens Class II / Q000276:immunology*; D006801:Humans; D017874:Immediate-Early Proteins / Q000494:pharmacology; D066298:In Vitro Techniques; D018396:Mucin-1 / Q000235:genetics*; D046988:Proteasome Endopeptidase Complex / Q000276:immunology; D012313:RNA; D013602:T-Lymphocytes, Cytotoxic / Q000276:immunology; D014158:Transcription, Genetic; D014162:Transfection; D014764:Viral Proteins / Q000494:pharmacology
D000939:Epitopes; D015395:Histocompatibility Antigens Class I; D000949:Histocompatibility Antigens Class II; C105843:ICP47 protein, Herpes simplex virus; D017874:Immediate-Early Proteins; D018396:Mucin-1; D014764:Viral Proteins; D012313:RNA; D046988:Proteasome Endopeptidase Complex