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Questions and Answers
Which stage of B cell development is characterized by heavy and light chain rearrangement?
Which stage of B cell development is characterized by heavy and light chain rearrangement?
What is the primary function of RAG-1 and RAG-2 in B cell development?
What is the primary function of RAG-1 and RAG-2 in B cell development?
Why is allelic exclusion an important part of B cell rearrangement?
Why is allelic exclusion an important part of B cell rearrangement?
What distinguishes naïve B cells from memory B cells?
What distinguishes naïve B cells from memory B cells?
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Which cell-surface interactions and cytokines are necessary for driving B cell activation and differentiation?
Which cell-surface interactions and cytokines are necessary for driving B cell activation and differentiation?
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What is the primary outcome of somatic hypermutation in B cells?
What is the primary outcome of somatic hypermutation in B cells?
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What is the function of Th1 cells in promoting class switching in B cells?
What is the function of Th1 cells in promoting class switching in B cells?
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Where are the heavy chain locus and the light chain loci located?
Where are the heavy chain locus and the light chain loci located?
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What is the significance of isotype or class switching in B cells?
What is the significance of isotype or class switching in B cells?
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How many Variable (V) regions are present in the heavy chain locus on chromosome 14?
How many Variable (V) regions are present in the heavy chain locus on chromosome 14?
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What is the role of CD40-CD40L interactions in B cell biology?
What is the role of CD40-CD40L interactions in B cell biology?
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What do Th2 cells secrete to promote class switching in B cells?
What do Th2 cells secrete to promote class switching in B cells?
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What is the function of helper T cells in promoting class switching in B cells?
What is the function of helper T cells in promoting class switching in B cells?
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What is the function of Variable region sequences in B cell biology?
What is the function of Variable region sequences in B cell biology?
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How does isotype or class switching further recombine the antibody heavy chain genes in B cells?
How does isotype or class switching further recombine the antibody heavy chain genes in B cells?
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Which of the following best describes the function of B cells?
Which of the following best describes the function of B cells?
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What is the primary role of memory B cells?
What is the primary role of memory B cells?
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Which surface marker is involved in recognizing C3d fragments deposited on pathogens?
Which surface marker is involved in recognizing C3d fragments deposited on pathogens?
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What is the consequence of failure to achieve tolerance in central tolerance B cells?
What is the consequence of failure to achieve tolerance in central tolerance B cells?
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What is the function of the B cell receptor (BCR)?
What is the function of the B cell receptor (BCR)?
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Which cells express both IgM and IgD?
Which cells express both IgM and IgD?
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What happens to activated B cells during differentiation?
What happens to activated B cells during differentiation?
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Which process allows for more rapid and robust secondary antibody response?
Which process allows for more rapid and robust secondary antibody response?
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Which enzyme plays a role in somatic hypermutation?
Which enzyme plays a role in somatic hypermutation?
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What is the role of CD19 in B cell activation?
What is the role of CD19 in B cell activation?
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What happens to activated B cells during differentiation?
What happens to activated B cells during differentiation?
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Which gene segments are joined in the early Pro-B cell stage?
Which gene segments are joined in the early Pro-B cell stage?
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What is the main event in the late Pro-B cell stage?
What is the main event in the late Pro-B cell stage?
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What happens to Pro-B cells that fail to produce a functional heavy chain?
What happens to Pro-B cells that fail to produce a functional heavy chain?
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What is formed by the heavy chain, surrogate light chain, Ig, and Igβ in Pro-B cells?
What is formed by the heavy chain, surrogate light chain, Ig, and Igβ in Pro-B cells?
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What is signaled for transcription to stop upon successful assembly of the pre-B cell receptor complex?
What is signaled for transcription to stop upon successful assembly of the pre-B cell receptor complex?
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What is the phenomenon termed when the B cell ensures it only expresses one of its two copies of the heavy chain genes?
What is the phenomenon termed when the B cell ensures it only expresses one of its two copies of the heavy chain genes?
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What reactivates RAG-1 and RAG-2 expression in pre-B cells?
What reactivates RAG-1 and RAG-2 expression in pre-B cells?
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What triggers immature B cells to shut down light chain rearrangement?
What triggers immature B cells to shut down light chain rearrangement?
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What occurs when a self-reactive, immature B cell is exposed to self-antigen?
What occurs when a self-reactive, immature B cell is exposed to self-antigen?
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What triggers mature B cells to become activated?
What triggers mature B cells to become activated?
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When does binding of the BCR with antigen trigger changes in gene expression in the nucleus?
When does binding of the BCR with antigen trigger changes in gene expression in the nucleus?
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Where does negative selection occur?
Where does negative selection occur?
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What is the function of protein kinases in the activation of the cell?
What is the function of protein kinases in the activation of the cell?
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Which cytokines are involved in B-cell activation?
Which cytokines are involved in B-cell activation?
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What is the function of memory B cells?
What is the function of memory B cells?
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Which surface molecule is synthesized by activated CD4 T cells during B-cell activation?
Which surface molecule is synthesized by activated CD4 T cells during B-cell activation?
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What is the role of CD40 binding to CD40L during B-cell activation?
What is the role of CD40 binding to CD40L during B-cell activation?
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Which antigens can activate B cells without requiring T cell help?
Which antigens can activate B cells without requiring T cell help?
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What is the function of B-1 cells in the immune system?
What is the function of B-1 cells in the immune system?
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What surface marker is normally found on immature B cells?
What surface marker is normally found on immature B cells?
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What is the main function of plasma cells?
What is the main function of plasma cells?
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Which type of B-cell expresses more sIgD than sIgM?
Which type of B-cell expresses more sIgD than sIgM?
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What do activated CD4 T cells secrete to trigger B-cell differentiation?
What do activated CD4 T cells secrete to trigger B-cell differentiation?
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What is the function of CD19 on B-cells?
What is the function of CD19 on B-cells?
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Study Notes
- B cells are crucial components of the adaptive immune response, responsible for recognizing and responding to antigens, secreting antibodies, and presenting antigens to T cells.
- Antibodies have five different classes (isotypes), each with unique effector functions and tissue distributions.
- Immunoglobulin genes undergo adaptive diversity through gene rearrangements, with RAG-1 and RAG-2 responsible for mediating the process.
- Malfunctions of RAG-1 and RAG-2 result in severe combined immune deficiency (SCID).
- B cell development consists of several stages: Pro-B to Pre-B cells, where heavy chains form pre-B receptors with surrogate light chains; elimination of self-reactive clones through central and peripheral tolerance; and maturation of B cells.
- Central tolerance eliminates self-reactive cells in the bone marrow, while peripheral tolerance eliminates self-reactive cells in the periphery.
- The B cell receptor complex includes the antibody molecule bound to Igα and Igβ, which mediate intracellular signaling, as well as surface molecules CD19, CD20, CD21, and CD81.
- B cells can be divided into several subsets, such as naïve, activated, plasma cells, and memory cells.
- Activated B cells undergo differentiation, with plasma cells producing and secreting antibodies, and memory cells providing long-term immunity.
- Somatic hypermutation, affinity maturation, and isotype switching occur post-activation, resulting in improved antibody production and response to antigens.
- T helper cells, cytokines, and activation-induced cytidine deaminase AID play essential roles in B cell activation, differentiation, and function.
- T-independent antigens elicit a different response from B cells compared to T-dependent antigens.
- B cells express various surface markers with distinct functions.
- Stem cells commit to the B-lineage in the bone marrow, with B cell development occurring in four phases: generation of B cells, early B cells, pre-B cells, and mature B cells.
- Early Pro-B cells rearrange heavy chain immunoglobulin genes and express CD19, while later Pro-B cells join the VH segment to the rearranged DJH segment.
- Rearrangement of heavy chain genes requires RAG-1, RAG-2, and TdT, with unproductive rearrangements leading to apoptosis.
- Pre-B cells express a pre-B cell receptor with a functional heavy chain and surrogate light chain.
- Central tolerance eliminates self-reactive cells by negative selection and receptor editing, while peripheral tolerance eliminates self-reactive cells by cell death or anergy.
- Mature B cells express both IgM and IgD and are considered naïve until they encounter their specific antigen.
- Activated B cells undergo differentiation into plasma cells, which secrete antibodies, and memory cells, which provide long-term immunity.
- Memory cells express CD27 and play a role in rapid and robust secondary antibody responses.
- CD19, CD21, and CD81 are involved in B cell activation and differentiation, with CD19 serving as the signaling chain of the complex.
- Somatic hypermutation, affinity maturation, and isotype switching lead to improved antibody production and response to antigens, with helper T cells, cytokines, and AID playing essential roles.
- T-independent antigens elicit a different response from B cells due to their structure and the absence of T cell help.
- Surface markers on B cells include CD19, CD20, CD21, CD23, CD24, CD27, and IgD, among others, each with distinct functions.
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Description
Test your knowledge on the differentiation of B-cells and their activation by specific antigens. Explore the process of B-cell precursor development from bone marrow stem cells and their transformation into functional plasma cell clones.