Abstract
Activation of T-helper cells is dependent upon the appropriate presentation of antigen-derived peptides on MHC class II molecules expressed on antigen presenting cells. In the current study we explored the repertoire of peptides presented on MHC class II molecules on human monocyte derived dendritic cells (moDCs) from four HLA-typed healthy donors. MHC class II-bound peptides could be routinely recovered from small cultures containing 5 × 10(6) cells. A fraction of the identified peptides were derived from proteins localized in the plasma membrane, endosomes, and lysosomes, but the majority of peptides that were presented on MHC class II originate from other organelles. Subsequently, we studied the antigen-specific peptide repertoire after endocytosis of a soluble antigen. Blood coagulation factor VIII (FVIII) was chosen as the antigen since our current knowledge on MHC class II presented peptides derived from this immunogenic therapeutic protein is limited. Analysis of the total repertoire of MHC class II-associated peptides revealed that per individual sample 20-50 FVIII-derived peptides were presented on FVIII-pulsed moDCs. Repertoires of FVIII-derived peptides eluted from moDCs derived from a panel of four HLA typed donors revealed that some MHC class II-presented FVIII peptides were presented by multiple donors, whereas the presentation of other FVIII peptides was donor-specific. In total 32 different core peptides were presented on FVIII-pulsed moDCs from four HLA-typed donors. Together our findings provide an unbiased approach to identify peptides that are presented by MHC class II on antigen-loaded moDCs from individual donors.
Highlights
IntroductionInspection of the repertoire of naturally occurring peptides presented on MHC class II molecules revealed that the majority of the presented peptides are derived from endogenous proteins [3, 4]
From the ‡Department of Plasma Proteins, Van Creveld Laboratory of UMC Utrecht and Sanquin Research, Amsterdam, The Netherlands, §Department of Immunopathology, Sanquin Research, Amsterdam, The Netherlands, ¶Utrecht Institute for Pharmaceutical Sciences, Utrecht University, Utrecht, The Netherlands, ʈSanquin-AMC Landsteiner Laboratory, Amsterdam, The Netherlands
Endogenous antigens are presented on MHC class I molecules for presentation to CD8ϩ T cells whereas peptides derived from exogenous, internalized antigens are loaded on MHC class II molecules and activate CD4 positive T cells
Summary
Inspection of the repertoire of naturally occurring peptides presented on MHC class II molecules revealed that the majority of the presented peptides are derived from endogenous proteins [3, 4]. Current efforts to probe the repertoire of antigen-derived naturally presented peptides are limited by the number of cells needed to obtain substantial amounts of MHC class II bound peptide. We show that per individual donor between 20 and 50 partially overlapping FVIII-specific peptides could be recovered from moDCs, corresponding to 8 –17 different potential CD4ϩ T-cell epitopes.
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
