What is the primary focus of the lecture on September 30, 2024?
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Antigen Processing and Presentation.
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What is the primary focus of the lecture on September 30, 2024?
Antigen Processing and Presentation.
What is the central role of MHC molecules?
To present antigens to T-cells.
How do MHC I and MHC II differ in terms of T cell recognition?
They are recognized by distinct T cell subsets and elicit different T cell responses.
Where are immature dendritic cells typically found?
In peripheral tissues, where they capture antigens.
What type of antigens are derived from endosomes or lysosomes?
Exogenous antigens.
Which department is Dr. Marcsilla Holub associated with?
Department of Genetics, Cell - and Immunobiology.
What happens if a T-cell becomes Th1?
It migrates to the periphery.
What is the role of macrophages in the cellular immune response?
They effectively clear bacteria.
What are the components of MHC I?
A peptide, an alpha chain, and a beta-2 microglobulin.
What types of pathogens can be found inside a cell?
Viruses, tumor antigens, intracellular bacteria (e.g., Mycobacterium), and extracellular bacteria (e.g., Neisseria gonorrhea).
What type of connection exists between MHC and peptide?
A firm connection.
What is the role of the endosome in antigen processing?
It facilitates the uptake of exogenous antigens for MHC II presentation.
Which university is hosting the lecture on Antigen Processing and Presentation?
Semmelweis University.
Which amino acids are structurally similar and important for anchoring in MHC Class I?
Tyrosine (Y), Phenylalanine (F), Leucine (L), Valine (V), and Isoleucine (I).
What type of peptides does TAP prefer for MHC I binding?
Peptides longer than 8 amino acids that are hydrophobic with carboxyl ends.
What is the typical peptide length for MHC Class II?
11-25 amino acids.
What type of binding structure does MHC Class I have?
Fixed pocket.
What are the two main pathways of receiving antigens?
Cytosol-derived (endogenous Ags) and endosome/lysosome-derived (exogenous Ags).
What type of antigens are derived from the cytosol?
Endogenous antigens.
What is the relationship between MHC I and antigen peptides?
MHC I and antigen peptides are physically separated but connect within the cell.
How do MHC and antigen peptides appear on the cell surface?
They appear always together on the cell surface.
What are peptides generated from?
Native proteins.
What types of peptides are presented by MHC I?
Self or viral protein peptides.
What is the primary goal of antigen presentation by dendritic cells?
To induce activation and determine the differentiation of naive T-cells (priming).
What types of pathogens can be found inside a cell?
Viruses, tumor antigens, intracellular bacteria (e.g., Mycobacterium), and extracellular bacteria (e.g., Neisseria gonorrhea).
What does TLR stand for in the context of dendritic cells?
Toll-like receptor.
Where are pathogens and their products located within a cell?
In either the cytosol or in vesicles.
What happens to immature dendritic cells upon activation?
They mature and enhance their ability to present antigens to T cells.
Where do peptides appear after being presented by MHC?
On the surface of cells.
How do B-lymphocytes select antigens?
By using their B-cell receptors (BCR).
What are immunogenic alloantigen proteins?
Proteins on the cell surface that can provoke an immune response.
What does the T-cell receptor recognize?
A complex of antigenic peptide and MHC.
What is the role of MHC in TCR recognition?
MHC presents the antigenic peptide to the T-cell receptor.
What is the role of the RER in relation to MHC I?
It is involved in the generation of MHC I + endogenous peptide complex.
What is the role of MHC I in the immune response?
It presents endogenous peptides to cytotoxic T-lymphocytes.
To whom are peptides presented?
To T cells.
What is the primary function of immature dendritic cells?
To capture and process antigens before migrating to lymph nodes.
How do dendritic cells influence CD4 lymphocyte differentiation?
By presenting antigens and utilizing TLR signaling.
What is meant by N- and C-terminal overhangs in peptides?
They refer to the portions of the peptide that extend beyond the anchor residues.
Where does MHC I + endogenous peptide travel to?
To the cell surface.
What is the role of the lysosome in antigen processing?
Degradation of proteins into 11-25 amino acid peptides.
How quickly is the viral peptide displayed on the surface of infected cells?
Within a very short time.
Which T cells recognize MHC I?
Cytotoxic T cells.
What does MHC stand for?
Major Histocompatibility Complex.
What does TCR stand for?
T-cell receptor.
Which types of cells express immunogenic alloantigen proteins?
All nucleated cells.
What type of peptides do MHC I molecules present?
Viral peptides.
What is an immature dendritic cell?
A precursor form of dendritic cells that has not yet fully developed its antigen-presenting capabilities.
What type of peptides do MHC II molecules activate?
Bacterial peptides.
Give an example of an intracellular bacterium.
Mycobacterium.
What are professional antigen presenting cells (APCs)?
Cells that present antigens to T-cells, including dendritic cells and macrophages.
Give an example of an extracellular bacterium.
Neisseria gonorrhea.
What is the function of HLA-DM?
It helps separate CLIP and loads MHC II with peptides.
Give an example of an intracellular bacterium.
Mycobacterium.
What is the role of B-cells and macrophages in antigen presentation?
They present antigens to effector T-cells to receive signals for maturation.
Where does the antigen-MHC complex develop?
On the cell surface.
What is the role of B-cell receptors?
To recognize whole antigens and initiate B-cell activation.
Are immunogenic alloantigen proteins present on all cells?
No, only on nucleated cells and some specific cells.
Where are pathogens and their products located within a cell?
In either the cytosol or in vesicles.
What is continuously degraded next to hydrophobic and basic amino acids?
Newly synthesized MHC I and its associated peptides.
What does MHC II do?
It presents exogenous peptides to helper T-lymphocytes.
What presents peptides on the surface of cells?
Major Histocompatibility Complex (MHC).
What is the typical peptide length for MHC Class I?
8-9 amino acids.
What structural feature do the important amino acids for MHC Class I anchoring have?
They are hydrophobic and contain phenol rings with 2 CH3 groups.
What are the MHC types mentioned in relation to peptide sequences?
MHC 'A1' and MHC 'A2'.
What is the significance of peptide length in MHC I binding?
TAP selectively transports peptides that are greater than 8 amino acids long.
What complex is formed with MHC I?
Peptide + MHC I make a complex.
What are HLA molecules?
Human Leukocyte Antigens.
What are the components of MHC II?
A peptide, an alpha chain, and a beta chain.
What is the significance of the association between MHC and peptide?
It forms a tight association essential for antigen presentation.
What is the role of the chaperone complex in MHC I peptide binding?
It assists in the proper folding and assembly of MHC I for peptide binding.
Can you provide an example of an MHC I-elicited response?
Cytotoxic T cell response to viral infection.
What is required for ATP-dependent peptide transport in MHC I processing?
TAP (Transporter associated with Antigen Processing).
What types of cells are included in phagocytes?
Natural dendritic cells and macrophages.
How are cytoplasmic peptides related to MHC I?
Cytoplasmic peptides become an integral part of MHC I.
What is the characteristic of peptides bound to MHC Class II molecules?
They lie at various distances from the ends of the peptide.
What type of cells express MHC Class II molecules?
Professional antigen-presenting cells (APCs) such as dendritic cells, macrophages, and B cells.
What is the primary function of MHC molecules?
To present peptide antigens to T cells.
What is the role of HLA-DM?
It facilitates the loading of peptides onto MHC II.
What do HLA molecules do in antigen presentation?
They present small antigen peptides to T-cells.
What is the significance of antigen presentation in the immune system?
It continuously informs the immune system about the outer and inner environment of various human cells.
Which faculty is hosting the lecture on Antigen Processing and Presentation?
Faculty of Dentistry.
Who is the lecturer for the Antigen Processing and Presentation session?
Dr. Marcsilla Holub.
What is the process of antigen uptake?
The process by which antigens are taken up for processing.
What role do dendritic cells play in the immune system?
They determine the differentiation pathway of CD4 lymphocytes.
Where does the partial degradation of Ii occur?
In the endoplasmic reticulum (RER) and Golgi apparatus.
What is an example of a bacterium associated with tumors?
Listeria monocytogenes.
What is CLIP in the context of MHC II?
A peptide that is removed by HLA-DM to load MHC II with other peptides.
What receptors do macrophages use to recognize antigens?
Complement receptors, Fc γ receptors, and lectin receptors.
What is the process called when dendritic cells activate naive T-cells?
Priming.
What is the role of mannose in antigen uptake?
It is recognized by specific receptors on B-cells.
What types of peptides are processed in the cytosol?
Normal self, transformed self (tumor), and viral peptides.
What are the two main types of antigen processing?
Endogenous and exogenous antigen processing.
What is the role of the proteasome in antigen processing?
Degradation of proteins into 8-9 amino acid peptides.
What is the role of T-cell receptors?
To recognize specific antigens presented by antigen presenting cells.
What is the function of TAP1 and TAP2?
They transport peptides into the RER for loading onto MHC I.
Which T cells recognize MHC II?
Helper T cells.
What stabilizes peptides bound to MHC Class I molecules?
The amino and carboxy termini of the peptide.
Where do dendritic cells carry pathogens to for antigen presentation?
To the lymph node.
Can you provide an example of an MHC II-elicited response?
Helper T cell activation in response to bacterial infection.
Which type of T-cell do dendritic cells present antigens to?
Naive T-cells.
What is CLIP in the context of MHC II processing?
CLIP is a fragment resulting from the partial degradation of Ii.
What happens to the MHC II complex in the acidic lysosome?
It binds to exogenous peptide to form the MHC II + exogenous peptide complex.
How is the length of peptides bound to MHC Class II molecules described?
Peptides are variable in length.
What does MHC stand for?
Major Histocompatibility Complex.
How do MHC Class I and Class II molecules differ in their peptide binding?
MHC Class I binds peptides that are 8-10 amino acids long, while MHC Class II binds longer peptides, typically 13-25 amino acids.
What do antigen presenting cells (APCs) do?
They process and present antigens to T-cells.
Which cells present MHC II?
Special antigen-presenting cells (APCs).
What complex is formed with MHC II during antigen processing?
MHC II αβ + Ii complex.
What is the significance of the peptides generated in the RER?
They are used to form complexes with MHC I for presentation.
What is an example of a bacterium associated with tumor antigens?
Listeria monocytogenes.
What type of binding structure does MHC Class II have?
Open cleft.
What are the two main classes of MHC molecules?
MHC Class I and MHC Class II.
What type of cells express MHC Class I molecules?
All nucleated cells.
What is the function of MHC molecules?
To present processed peptides to T-cells.
Give an example of an extracellular bacterium.
Neisseria gonorrhea.
What are anchor residues in the context of MHC Class II molecules?
Anchor residues are fixed places within the peptide.
What is the difference between linear and conformational epitopes?
Linear epitopes are processed peptides, while conformational epitopes are whole molecules.
What is C3b's role in antigen uptake?
It acts as an opsonin that enhances phagocytosis.
What is the role of the proteasome in peptide processing?
It cleaves proteins into peptides.
What is TAP and its function?
TAP inserts peptides into the Rough Endoplasmic Reticulum (RER).
Where does endogenous antigen processing occur?
Inside the cytosol.
What recognizes the MHC I-peptide complex?
Cytotoxic T lymphocytes (Tc).
Where is a large amount of MHC I found?
In the Rough Endoplasmic Reticulum (RER).
Which cells present MHC I?
Every nucleated cell.
