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Questions and Answers
What is the main focus of Chapter 5 in the course material?
What is the main focus of Chapter 5 in the course material?
Which of the following best describes the receptors produced by B-cells and T-cells?
Which of the following best describes the receptors produced by B-cells and T-cells?
What aspect of the immune system is highlighted by the diversity of receptors?
What aspect of the immune system is highlighted by the diversity of receptors?
Which chapters will be covered in the next module focused on B cells?
Which chapters will be covered in the next module focused on B cells?
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What is the primary function of B-cell receptors (BCRs)?
What is the primary function of B-cell receptors (BCRs)?
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Which part of the immune system has a limited number of receptors that remain consistent across individuals?
Which part of the immune system has a limited number of receptors that remain consistent across individuals?
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What is a key characteristic of the immune receptors mentioned?
What is a key characteristic of the immune receptors mentioned?
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Which of the following components is associated with B-cell receptors?
Which of the following components is associated with B-cell receptors?
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How do receptors of the adaptive immune system achieve diversity?
How do receptors of the adaptive immune system achieve diversity?
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Which of the following is NOT an objective of the lecture?
Which of the following is NOT an objective of the lecture?
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Which statement is true regarding T-cell receptors (TCRs)?
Which statement is true regarding T-cell receptors (TCRs)?
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What is the expected outcome of somatic chromosomal rearrangements in lymphocytes?
What is the expected outcome of somatic chromosomal rearrangements in lymphocytes?
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What initiates the intracellular signaling cascade upon BCR binding an epitope?
What initiates the intracellular signaling cascade upon BCR binding an epitope?
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What is the main reason for the deletion of the δ-chain locus during TCR γ & δ locus rearrangement?
What is the main reason for the deletion of the δ-chain locus during TCR γ & δ locus rearrangement?
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Which of the following best describes the organization of the TCR γ locus?
Which of the following best describes the organization of the TCR γ locus?
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How many Cδ gene segments are present in the δ locus?
How many Cδ gene segments are present in the δ locus?
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Why is the study of a specific subset of T cells highlighted by Kristel Yee Mon, Ph.D.?
Why is the study of a specific subset of T cells highlighted by Kristel Yee Mon, Ph.D.?
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What challenge related to diversity in the field of immunology is mentioned in Kristel Yee Mon's statement?
What challenge related to diversity in the field of immunology is mentioned in Kristel Yee Mon's statement?
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What type of cells do activated B cells differentiate into that secrete antibodies?
What type of cells do activated B cells differentiate into that secrete antibodies?
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What is the primary function of antibodies?
What is the primary function of antibodies?
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What component is part of the T-cell receptor (TCR) complex that helps link TCR with intracellular signaling?
What component is part of the T-cell receptor (TCR) complex that helps link TCR with intracellular signaling?
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Which accessory molecule can serve as a coreceptor for the T-cell receptor?
Which accessory molecule can serve as a coreceptor for the T-cell receptor?
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Which statement correctly describes the T-cell receptor (TCR)?
Which statement correctly describes the T-cell receptor (TCR)?
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What is the primary characteristic of the antibodies secreted by plasma cells?
What is the primary characteristic of the antibodies secreted by plasma cells?
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What is an Fab fragment in the context of T-cell receptors?
What is an Fab fragment in the context of T-cell receptors?
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Which molecules are involved in recognizing antigens in T lymphocytes?
Which molecules are involved in recognizing antigens in T lymphocytes?
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What is the role of the complementarity-determining regions (CDR) in T-cell receptors?
What is the role of the complementarity-determining regions (CDR) in T-cell receptors?
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Which statement best describes the relationship between the α and β chains of a T-cell receptor?
Which statement best describes the relationship between the α and β chains of a T-cell receptor?
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How is the diversity of T-cell receptors generated?
How is the diversity of T-cell receptors generated?
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Which of the following components is NOT associated with the core T-cell receptor complex?
Which of the following components is NOT associated with the core T-cell receptor complex?
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What type of protein interactions facilitate the association of the TCR with CD3 proteins?
What type of protein interactions facilitate the association of the TCR with CD3 proteins?
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What are hypervariable regions in the context of T-cell receptors?
What are hypervariable regions in the context of T-cell receptors?
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Which type of T-cell receptor includes γ and δ chains?
Which type of T-cell receptor includes γ and δ chains?
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During α-chain rearrangement, which gene segments are involved?
During α-chain rearrangement, which gene segments are involved?
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What is the functional significance of the T-cell receptor complex's composition?
What is the functional significance of the T-cell receptor complex's composition?
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Which part of the T-cell receptor is primarily responsible for binding to the pMHC molecule ligand?
Which part of the T-cell receptor is primarily responsible for binding to the pMHC molecule ligand?
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What is the primary function of the CD3 proteins in relation to the TCR?
What is the primary function of the CD3 proteins in relation to the TCR?
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What types of antigenic specificity do T-cell receptors recognize?
What types of antigenic specificity do T-cell receptors recognize?
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How do γδ T-cell receptors differ from αβ T-cell receptors?
How do γδ T-cell receptors differ from αβ T-cell receptors?
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In T-cell receptor gene rearrangement, what does the D stand for in V, D, J segments?
In T-cell receptor gene rearrangement, what does the D stand for in V, D, J segments?
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Study Notes
Somatically Generated Receptors of the Adaptive Immune System
- Receptors created in lymphocytes of an individual through random somatic chromosomal rearrangements and mutations
- Vast array of receptors specific for molecular details found in unique epitopes
Cell Surface Receptor Diversity
- Receptors of the innate immune system (PRRs and complement receptors) are limited in number and diversity
- Somatically generated receptors of lymphocytes in the adaptive immune system use random combinations of genes
Immunoglobulins (Ig) & T-cell receptors (TCRs)
- Antigen receptors of adaptive immunity
B -Cell Receptors
- Cell surface bound monomeric immunoglobulin associated with disulfide-linked heterodimers called Igα & Igβ
- BCR binds an epitope
- Specialized cytoplasmic tails of Igα & Igβ activate an intracellular signaling cascade that leads to B-cell activation
- Some activated B cells terminally differentiate into plasma cells that secrete immunoglobulins
T-Cell receptors (TCRs)
- Heterodimers, consisting of either an αβ or a γδ chain pair
- Always membrane bound and recognize antigen combined with MHC molecules
- Associated with CD3 complex
- CD3 complex links TCR to intracellular signaling molecules.
- An accessory molecule (CD4 OR CD8) serves as a coreceptor for TCR *
The T-cell Receptor Resembles a Membrane-bound Fab Fragment of Immunoglobulin
- Membrane-bound heterodimer composed of an α chain and a β chain
- Extracellular portion of each chain contains two immunoglobulin-like domains:
- Constant (C) domain
- Variable (V) domain
- The 3D structure formed by the 4 immunoglobulin-like domains of TCR resembles the antigen-binding Fab fragment of antibody
T-cell receptor diversity is generated by gene rearrangement.
- DNA recombination assembles a V-region sequence for each chain
- For α chain, rearrangement of a Vα gene segment and a Jα gene segment creates a functional exon encoding the V domain.
- For β chain, rearrangement of a Vβ , a Dβ, & a Jβ gene segment creates functional V-domain exon.
- The assembled genes are transcribed and spliced to produce mRNA encoding α & β chains.
Expression of the T-cell receptor on the T-cell surface requires association with additional proteins
- α & β chains bind antigen and form core TCR
- This core αβ heterodimer associates with CD3γ & CD3δ & CD3ε & the ζ chain
- Transmembrane domains of α & β chains contain positively charged amino acids (+) that form strong electrostatic interactions with negatively charged amino acids (–) in transmembrane regions of CD3γ, δ, & ε chains.
There are two classes of T-cell receptor
- αβ T-cell receptor and γδ T-cell receptor have similar structures but different functions
The Organization of the Human T-cell Receptor γ-chain and δ-chain loci
- TCR γ & δ loci (like α & β loci) contain sets of variable (V), diversity (D), joining (J), & constant (C) gene segments
- δ locus is located within α-chain locus on chromosome 14, between clusters of Vα & Jα gene segments
- There are at least 3 Vδ gene segments, 3 Dδ gene segments, 3 Jδ gene segments, & 1 Cδ gene segment
- Vδ segments are interspersed among Vα and other gene segments
- This arrangement means that DNA rearrangement within α-chain locus results in deletion of δ-chain locus.
- The γ locus (chromosome 7) resembles β locus, with 1 set of V segments & 2 C gene segments each with its own set of J segments.
Kristel Yee Mon, Ph.D.
- Studying a rare subset of T cells that may be a biomarker for patient outcome after infection with SARS-CoV2
- Studying chemically enhancing innate immune cell types to better prime anti-tumor T cell killer function as a prospective cancer immunotherapy agent.
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Description
Test your knowledge on the somatically generated receptors of the adaptive immune system. This quiz covers the diversity of immunoglobulins, T-cell receptors, and B-cell receptors, emphasizing the mechanisms behind their activation and function. Dive into the complexity of immune responses and receptor formations.
