40 Questions
What is the function of dendritic cells (DCs) in the immune system?
Capturing and presenting antigens
Which cells are considered antigen-presenting cells (APCs)?
Macrophages, dendritic cells, and B cells
Why are antigen-presenting cells (APCs) particularly efficient in antigen presentation?
Their high expression of MHC molecules and co-stimulatory molecules
Where do dendritic cells (DCs) migrate to after capturing antigens?
Secondary lymphoid organs like lymph nodes
What is the main function of CD4+ helper T cells upon activation by APCs?
Stimulating B cells, activating cytotoxic T cells, or enhancing other immune cell activities
What is the purpose of antigen receptor gene rearrangement in T cells?
To generate diversity in antigen receptor genes required for recognizing foreign antigens
Which gene segments are involved in the recombination process to generate diversity in TCR Alpha chains?
V and D
What is the primary function of the RAG complex during gene rearrangement in B and T cell development?
Recombine V, D, and J gene segments
At which lymphocyte maturation checkpoint does positive selection for MHC recognition occur?
Double-Positive (DP) Stage
What is the main outcome of the gene rearrangement process in B and T cells?
Generation of combinatorial diversity in antigen receptor genes
During gene rearrangement in the TCR Beta Chain Locus, what is the role of combinatorial diversity?
It refers to the random combination of V, D, and J gene segments.
Which process introduces additional diversity through the imprecise joining of gene segments within the TCR Beta Chain Locus?
Junctional diversity
What is the main function of central tolerance during lymphocyte maturation?
To test if T cells can recognize self-MHC molecules
Which scenario would cause a lymphocyte to fail the peripheral tolerance checkpoint?
Strong recognition of self-antigens by mature lymphocytes
What is the term used to describe the event where lymphocytes respond to self-antigens, leading to autoimmune reactions?
Auto-reactivity
What is the role of anchor amino acids within a peptide sequence in peptide binding to MHC molecules?
Interact with specific pockets in the MHC molecule
Why do different individuals express unique combinations of MHC alleles?
Because of the polymorphic nature of MHC molecules
Which pathway describes antigen processing for display by class II MHC molecules?
Involvement of the extracellular antigens internalized via endocytosis
How are peptide fragments generated from endogenous proteins transported into the endoplasmic reticulum for class I MHC molecule binding?
Transportation by TAP proteins
What contributes to individual differences in peptide presentation and immune responses?
Combinatorial diversity of TCR and BCR sequences
What is the primary mode of interaction between the TCR and MHC-peptide complex?
Interaction through the variable regions of the TCR chains and the peptide antigen
What role do ITAMs play in T cell activation?
Initiating intracellular signaling cascades
Which co-receptor enhances the binding of the TCR to the peptide-MHC complex?
CD4
What is the role of Lck in a T cell upon TCR engagement?
Modifying ITAM-containing proteins through tyrosine kinase activity
Which component of the TCR complex recognizes MHC class I molecules?
CD8
What determines the immunodominance of an epitope?
Affinity for MHC molecules
What is the main function of a T cell receptor (TCR)?
Recognize specific peptide antigens
What is the role of co-receptors CD4 and CD8 on T cells?
Directly interact with MHC molecules
What ensures specificity in antigen recognition by T cells?
Clonal selection and expansion of T cells
Which of the following factors does NOT influence the immunodominance of an epitope?
Expression level on APCs
What is the role of the pre-T cell receptor during T cell development?
Initiating proliferation and differentiation of T cells
Which stage of T cell development is characterized by the expression of both CD4 and CD8 co-receptors?
Double-Positive (DP) Stage
At which lymphocyte maturation checkpoint does negative selection for self-reactivity occur?
Single-Positive (SP) Stage
In response to signaling from the pre-T cell receptor, what happens to T cells?
They undergo proliferation and differentiation.
What is required for the activation and signaling of the pre-T cell receptor?
Expression of CD3 signaling chains (ε, δ, γ)
Which type of T cells express the CD4 co-receptor?
Helper T cells
What is the main function of the Double-Negative (DN) Stage in T cell development?
Commitment to T cell lineage
'Single-Positive (SP)' stage refers to the expression of which co-receptor by a T cell?
'CD4' co-receptor
'Mature T Cell Stage' involves the exit from thymus to which type of organs?
'Secondary immune organs'
'Combinatorial diversity' in T cell receptors arises due to variations in which chains?
'Alpha and beta' chains
Explore the TCR Beta Chain Locus and the generation of diversity in the expressed protein through V, D, and J gene segments rearrangement. Learn about combinatorial diversity and junctional diversity introduced by the random combination of gene segments and imprecise joining. Dive into Chapter 13 for more insights.
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