Podcast
Questions and Answers
What are the 3 broad classes of T cells?
What are the 3 broad classes of T cells?
Which classes of T cells are CD4?
Which classes of T cells are CD4?
Which classes of T cells are CD8?
Which classes of T cells are CD8?
How many antigen binding sites does a T cell receptor have?
How many antigen binding sites does a T cell receptor have?
Signup and view all the answers
How many hypervariable regions make up the T cell antigen binding site?
How many hypervariable regions make up the T cell antigen binding site?
Signup and view all the answers
What is the function of the T cell receptor constant regions?
What is the function of the T cell receptor constant regions?
Signup and view all the answers
What 3 processes are responsible for generating T-cell receptor diversity?
What 3 processes are responsible for generating T-cell receptor diversity?
Signup and view all the answers
What gene segments make up the α-chain variable region of the T cell receptor?
What gene segments make up the α-chain variable region of the T cell receptor?
Signup and view all the answers
What gene segments make up the β-chain variable region of the T cell receptor?
What gene segments make up the β-chain variable region of the T cell receptor?
Signup and view all the answers
Are the constant regions of the T cell receptor composed of gene segments?
Are the constant regions of the T cell receptor composed of gene segments?
Signup and view all the answers
What type of antigen do T cells recognize and what type of molecule must the antigen be presented on?
What type of antigen do T cells recognize and what type of molecule must the antigen be presented on?
Signup and view all the answers
From what location are the presented antigens for MHC class I derived?
From what location are the presented antigens for MHC class I derived?
Signup and view all the answers
From what location are the presented antigens for MHC class II derived?
From what location are the presented antigens for MHC class II derived?
Signup and view all the answers
What type of T cells are activated by MHC class I?
What type of T cells are activated by MHC class I?
Signup and view all the answers
What type of T cells are activated by MHC class II?
What type of T cells are activated by MHC class II?
Signup and view all the answers
Which cell types express MHC class I molecules?
Which cell types express MHC class I molecules?
Signup and view all the answers
Which cell types express MHC class II molecules?
Which cell types express MHC class II molecules?
Signup and view all the answers
Which T cell co-receptor (CD4 or CD8) binds to MHC class I?
Which T cell co-receptor (CD4 or CD8) binds to MHC class I?
Signup and view all the answers
Which T cell co-receptor (CD4 or CD8) binds to MHC class II?
Which T cell co-receptor (CD4 or CD8) binds to MHC class II?
Signup and view all the answers
What is cross-presentation?
What is cross-presentation?
Signup and view all the answers
Why is it necessary for dendritic cells to sometimes use cross presentation?
Why is it necessary for dendritic cells to sometimes use cross presentation?
Signup and view all the answers
How many different MHC class I and II molecules does each person have for presenting antigens?
How many different MHC class I and II molecules does each person have for presenting antigens?
Signup and view all the answers
The MHC genes are the most polymorphic genes in the genome. What does polymorphic mean?
The MHC genes are the most polymorphic genes in the genome. What does polymorphic mean?
Signup and view all the answers
Why is it beneficial for the human population to have such a large number of different MHC alleles?
Why is it beneficial for the human population to have such a large number of different MHC alleles?
Signup and view all the answers
How are only 12 MHC molecules in each person able to present such a broad range of antigens from all of the many pathogens encountered by the body?
How are only 12 MHC molecules in each person able to present such a broad range of antigens from all of the many pathogens encountered by the body?
Signup and view all the answers
What determines which antigens will bind to a particular MHC molecule?
What determines which antigens will bind to a particular MHC molecule?
Signup and view all the answers
What is MHC restriction?
What is MHC restriction?
Signup and view all the answers
What is a peptide binding motif?
What is a peptide binding motif?
Signup and view all the answers
Which MHC class I molecules are involved in antigen presentation?
Which MHC class I molecules are involved in antigen presentation?
Signup and view all the answers
Which MHC class II molecules are involved in antigen presentation?
Which MHC class II molecules are involved in antigen presentation?
Signup and view all the answers
Study Notes
T Cell Overview
- T cells can be classified into three broad categories: Helper, Regulatory, and Cytotoxic.
- Helper and Regulatory T cells express the co-receptor CD4, while Cytotoxic T cells express CD8.
T Cell Receptor (TCR) Structure
- A T cell receptor has a single antigen-binding site.
- The antigen-binding site consists of six hypervariable regions.
- Constant regions of the TCR provide structural support and anchor the receptor to the cell membrane.
- The α-chain variable region is formed from gene segments V and J.
- The β-chain variable region is formed from gene segments V, D, and J.
- Constant regions are not composed of gene segments.
Antigen Recognition and Presentation
- T cells recognize antigens as peptides presented by Major Histocompatibility Complex (MHC) molecules.
- MHC class I presents antigens derived from the cytosol, while MHC class II presents antigens derived from the extracellular environment or endosomal system.
T Cell Activation
- CD8 T cells are activated by MHC class I molecules.
- CD4 T cells are activated by MHC class II molecules.
- MHC class I molecules are expressed by most body cells, which can be infected by intracellular pathogens.
- MHC class II molecules are primarily expressed by professional antigen-presenting cells: dendritic cells, macrophages, and B cells.
Co-receptors and Antigen Presentation
- The CD8 co-receptor binds to MHC class I.
- The CD4 co-receptor binds to MHC class II.
- Cross-presentation enables dendritic cells to present extracellular antigens on MHC class I to activate CD8 T cells even if they are not infected.
Diversity of MHC and T Cells
- Each person has 6 MHC class I molecules and 6 MHC class II molecules, inherited from both parents.
- MHC genes are the most polymorphic in the genome, meaning each gene has many different alleles.
- A large variety of MHC alleles enhances the immune system's ability to present a wide range of antigens, making it less likely for pathogens to evade detection.
MHC Functionality
- MHC molecules exhibit promiscuous binding affinity, allowing them to bind a diverse range of peptide antigens.
- Peptides must have specific anchor residues to bind to a particular MHC molecule, determining which antigens will be presented.
- MHC restriction refers to the specificity of a T cell receptor for both the antigen and the associated MHC molecule.
- The peptide binding motif is characterized by the sequence of anchor residues that interact with MHC molecules.
MHC Class Specificity
- MHC class I molecules involved in antigen presentation include A, B, and C.
- MHC class II molecules involved in antigen presentation include DP, DQ, and DR.
Studying That Suits You
Use AI to generate personalized quizzes and flashcards to suit your learning preferences.
Description
Test your knowledge on T cell receptors and MHC molecules with these flashcards. Dive into the specifics of T cell classes and their functions, including the roles of CD4 and CD8 cells. Perfect for students studying immunology or related fields.
