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Questions and Answers
What is the primary function of TH cells in B cell response?
What is the primary function of TH cells in B cell response?
What happens to memory B cells formed during a primary response?
What happens to memory B cells formed during a primary response?
Where do antigen-antibody complexes enter the lymph node?
Where do antigen-antibody complexes enter the lymph node?
What is the result of antigen-mediated B-cell activation in lymph nodes?
What is the result of antigen-mediated B-cell activation in lymph nodes?
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What is the result of antibody-mediated suppression on the humoral response?
What is the result of antibody-mediated suppression on the humoral response?
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Why are certain vaccines not administered to infants before the age of 1 year?
Why are certain vaccines not administered to infants before the age of 1 year?
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What is the primary site of B cell activation?
What is the primary site of B cell activation?
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What is the primary function of antibodies in the humoral immune response?
What is the primary function of antibodies in the humoral immune response?
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What is the time frame for germinal center formation?
What is the time frame for germinal center formation?
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What is the primary function of germinal centers?
What is the primary function of germinal centers?
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What is the characteristic of a primary response to antigen?
What is the characteristic of a primary response to antigen?
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What is the result of B-cell differentiation in germinal centers?
What is the result of B-cell differentiation in germinal centers?
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What is the result of the immune system encountering an antigen?
What is the result of the immune system encountering an antigen?
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What is the role of antigen-antibody complexes in lymph nodes?
What is the role of antigen-antibody complexes in lymph nodes?
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Why is it necessary to regulate the immune effector response?
Why is it necessary to regulate the immune effector response?
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What happens to naive B cells during a primary response?
What happens to naive B cells during a primary response?
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Where do Progenitor B Cells proliferate?
Where do Progenitor B Cells proliferate?
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What is required for the development of immature B cells into precursor B cells?
What is required for the development of immature B cells into precursor B cells?
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What type of antigens require direct contact with TH cells?
What type of antigens require direct contact with TH cells?
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What is the characteristic of TI-1 antigens?
What is the characteristic of TI-1 antigens?
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What is the result of TI-1 antigen binding to B cells?
What is the result of TI-1 antigen binding to B cells?
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What is the role of stromal cells in the bone marrow?
What is the role of stromal cells in the bone marrow?
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What is the characteristic of an immature B cell?
What is the characteristic of an immature B cell?
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What is required for a B cell to be fully functional?
What is required for a B cell to be fully functional?
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What is the result of active immunization?
What is the result of active immunization?
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What is a key consideration in designing vaccines for active immunization?
What is a key consideration in designing vaccines for active immunization?
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What is the purpose of attenuating microorganisms in vaccine development?
What is the purpose of attenuating microorganisms in vaccine development?
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What is a characteristic of inactivated whole pathogenic organisms used in vaccine development?
What is a characteristic of inactivated whole pathogenic organisms used in vaccine development?
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What is the effect of heat inactivation on proteins?
What is the effect of heat inactivation on proteins?
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What type of immune response is elicited by inactivated whole pathogenic organisms?
What type of immune response is elicited by inactivated whole pathogenic organisms?
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Why are booster doses required for inactivated whole pathogenic organisms?
Why are booster doses required for inactivated whole pathogenic organisms?
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What is the goal of vaccine designers when developing a vaccine?
What is the goal of vaccine designers when developing a vaccine?
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Which type of cells express the highest levels of class I MHC molecules?
Which type of cells express the highest levels of class I MHC molecules?
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What is the main function of antigen-presenting cells?
What is the main function of antigen-presenting cells?
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Which type of MHC molecules are expressed constitutively by antigen-presenting cells?
Which type of MHC molecules are expressed constitutively by antigen-presenting cells?
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What is the term for the process of degrading protein antigens into peptides that can be presented by MHC molecules?
What is the term for the process of degrading protein antigens into peptides that can be presented by MHC molecules?
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What type of cells are restricted to recognizing antigen presented by MHC Class II molecules?
What type of cells are restricted to recognizing antigen presented by MHC Class II molecules?
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What is the term for the complex formed by the association of a peptide with an MHC molecule?
What is the term for the complex formed by the association of a peptide with an MHC molecule?
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What type of antigens are processed and presented by Class I MHC molecules?
What type of antigens are processed and presented by Class I MHC molecules?
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What is the term for the cells that are killed by cytotoxic T cells?
What is the term for the cells that are killed by cytotoxic T cells?
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Study Notes
B-Cell Development
- Progenitor B cells proliferate in the bone marrow, where they develop into immature B cells with the help of stromal cells and IL-7.
- Pro-B cells undergo heavy chain rearrangement, while pre-B cells undergo light chain rearrangement.
- Immature B cells are committed to antigenic specificity and produce IgM, but they are not fully functional until they express both IgM and IgD on their membrane.
B-Cell Activation and Proliferation
- After export from the bone marrow, B cells undergo activation, proliferation, and differentiation in the periphery, requiring antigen.
- Thymus-independent (TI) antigens, such as lipopolysaccharide (LPS), can activate B cells through innate receptors, leading to a polyclonal response.
- Thymus-dependent (TD) antigens require direct contact with TH cells for B cell activation.
B-Cell Activation
- TH cells play an essential role in B cell response, and interaction between B cells and T cells occurs in the lymph nodes.
- In vivo, B cells are activated in peripheral lymphoid organs, such as the spleen and lymph nodes, where they differentiate into plasma cells secreting IgM and IgG.
Germinal Centers and Antigen-Induced B-Cell Differentiation
- Germinal centers arise within 7-10 days after initial exposure to thymus-dependent antigen in lymph nodes.
- Three important B-cell differentiation events occur in germinal centers: affinity maturation, class switching, and formation of plasma and memory B cells.
The Humoral Response
- The humoral immune response is carried out by antibodies produced by activated B cells.
- Primary and secondary responses differ significantly, with primary responses characterized by a lag phase and secondary responses resulting in a more rapid and robust response.
Regulation of the Immune Effector Response
- Humoral and cell-mediated branches must be heavily regulated to prevent over-activation.
- The immune system can either develop an immune response or enter a state of tolerance upon encountering an antigen.
- MHC restriction is important, with CD8+ Tc cells recognizing antigen presented by MHC Class I molecules and CD4+ TH cells recognizing antigen presented by MHC Class II molecules.
Antigen Processing and Presentation
- Antigen processing involves the degradation of protein antigens into peptides, which then associate with MHC molecules and are transported to the membrane for display.
- Class I MHC molecules bind peptides derived from endogenous antigens, while Class II MHC molecules bind peptides derived from exogenous antigens.
Designing Vaccines for Active Immunization
- Several factors must be considered when developing a successful vaccine, including the activation of the humoral or cell-mediated branch and the development of immunologic memory.
- Whole-organism vaccines can be attenuated to lose their pathogenicity but retain their capacity for transient growth, or inactivated to elicit a humoral immune response.
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Description
Learn about the development and activation of B cells, including their proliferation in the bone marrow, antigenic specificity, and IgM and IgD expression.
