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Immunology
03.05.2017, Ruhr-Universität Bochum
Marcus Peters, marcus.peters@rub.de
Antigenpresentation
Important Abbreviations: MHC --- Major Histocompatibility Complex HLA --- Human Leucocyte Antigen
MHC I = HLA-A, HLA-B, HLA-V MHC II = Alpha-chain Beta-chain HLA-DMA HLA-DMB HLA-DOA HLA-DOB HLA-DPA1 HLA-DPB1 HLA-DQA1, HLA-DQA2 HLA-DQB1, HLA-DQB2 HLA-DRA HLA-DRB1, HLA-DRB3, HLA-DRB4, HLA-DRB5
Cells consist of different compartiments
MHC I molecules are expressed by every nucleated cell MHC II molecules are expressed by antigen presenting cells only
Overview of antigen presenting cells and their functions
Characterization of the antigen presenting molecules MHC
On MHC I molecules are displayed that are derived from
the cytosol
CD8 exprimierende zytotoxische T-Zelle
Loading of MHC I with peptides
Transportation of the MHC I peptide complex to the cell surface
ERAP=endoplasmic reticulum aminopeptidase UGT=UDP-glucuronosyltransferase TAP= Transporter associated with antigen processing
Molecular structure of MHC I
Conserved amino acids coordinate the binding of peptides to MHC I
Coordination of the MHC1 binding peptide
MHCI/Peptid Komplex in Interaktion mit dem T-Zell-Rezeptor
Antigen präsentierende Zelle
Zytotoxische T-Zelle
On MHC II molecules are displayed that are derived from
the extracellular medium
CD4 exprimierende T-Helfer-Zelle
Loading of MHC II with peptides
Molecular structure of MHC II
Binding of peptides to MHC II
T-Helfer-Zelle
Antigen präsentierende Zelle
MHCII/Peptid Komplex in Interaktion mit dem T-Zell-Rezeptor
Both the MHC and the appropriate antigenic peptide must be Recognized by the T cell
Genomic organization of the MHC on chromosome no. 6
Polygenie
Polymorphism and Polygenism increase the variability of MHC molecules
Codominat expression of MHC alleles!
Allelic variabilty is concentrated on the peptide binding region of MHC
One specific MHC molecule is able to bind several different peptides
Enumeration of the known diversity of MHC alleles in human
Strategies used by pathogens to evade the immune response by affecting antigen presentation
Different situations may lead to the rejection of a non-compatible transplant
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