Disruption of Multivesicular Body Vesicles Does Not Affect Major Histocompatibility Complex (MHC) Class II-Peptide Complex Formation and Antigen Presentation by Dendritic Cells*
| Autor: | Sanjay Khandelwal, Laura Santambrogio, Paul A. Roche, Erica L. Heipertz, Brian Scharf, Adam C. Berger, Berta Bosch |
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| Rok vydání: | 2013 |
| Předmět: |
CD4-Positive T-Lymphocytes
endocrine system T cell Immunology Antigen presentation macromolecular substances Lymphocyte Activation Major histocompatibility complex environment and public health Biochemistry Mice Antigen Niemann-Pick C1 Protein medicine Animals Antigens Multivesicular Body Antigen-presenting cell Molecular Biology Mice Knockout Antigen Presentation Mice Inbred BALB C MHC class II biology Antigen processing Histocompatibility Antigens Class II Intracellular Signaling Peptides and Proteins Proteins Dendritic Cells Cell Biology Cell biology medicine.anatomical_structure biology.protein lipids (amino acids peptides and proteins) biological phenomena cell phenomena and immunity Peptides |
| Zdroj: | Journal of Biological Chemistry. 288:24286-24292 |
| ISSN: | 0021-9258 |
| Popis: | The antigen processing compartments in antigen-presenting cells (APCs) have well known characteristics of multivesicular bodies (MVBs). However, the importance of MVB integrity to APC function remains unknown. In this study, we have altered the ultrastructure of the MVB by perturbing cholesterol content genetically through the use of a deletion of the lipid transporter Niemann-Pick type C1 (NPC1). Immunofluorescence and electron microscopic analyses reveal that the antigen processing compartments in NPC1−/− dendritic cells (DCs) have an abnormal ultrastructure in that the organelles are enlarged and the intraluminal vesicles are almost completely absent and those remaining are completely disorganized. MHC-II is restricted to the limiting membrane of these enlarged MVBs where it colocalizes with the peptide editor H2-DM. Curiously, proteolytic removal of the chaperone protein Invariant chain from MHC-II, degradation of internalized foreign antigens, and antigenic-peptide binding to nascent MHC-II are normal in NPC1−/− DCs. Antigen-pulsed NPC1−/− DCs are able to effectively activate antigen-specific CD4 T cells in vitro, and immunization of NPC1−/− mice reveals surprisingly normal CD4 T cell activation in vivo. Our data thus reveal that the localization of MHC-II on the intraluminal vesicles of multivesicular antigen processing compartments is not required for efficient antigen presentation by DCs. Background: The antigen processing compartments in APCs possess a multivesicular morphology. Results: APCs lacking multivesicular bodies can effectively process and present antigens to T cells. Conclusion: Multivesicular body integrity is not required for antigen presentation. Significance: Understanding the nature of antigen processing compartments is important for understanding mechanisms of T cell activation. |
| Databáze: | OpenAIRE |
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