Podcast
Questions and Answers
Antibodies are secreted proteins that recognize 'epitopes' on the surface of pathogens.
Antibodies are secreted proteins that recognize 'epitopes' on the surface of pathogens.
True (A)
Epitopes can only be proteins.
Epitopes can only be proteins.
False (B)
The constant region of an antibody is responsible for activating different effectors.
The constant region of an antibody is responsible for activating different effectors.
True (A)
The type of constant region determines the isotype of an antibody.
The type of constant region determines the isotype of an antibody.
The Fab portion of an antibody is responsible for activating immune cells.
The Fab portion of an antibody is responsible for activating immune cells.
Antibodies can recognize parts of an antigen known as epitopes.
Antibodies can recognize parts of an antigen known as epitopes.
The variable regions of antibodies are involved in binding to antigens.
The variable regions of antibodies are involved in binding to antigens.
Antibodies are only effective against viruses.
Antibodies are only effective against viruses.
B cells that bind to self-peptide too tightly are removed by positive selection.
B cells that bind to self-peptide too tightly are removed by positive selection.
Naïve B cells leave the bone marrow with a functioning BCR.
Naïve B cells leave the bone marrow with a functioning BCR.
B cell activation requires only one signal from T helper cells.
B cell activation requires only one signal from T helper cells.
During B cell activation, T cells and B cells must come together in the lymph node.
During B cell activation, T cells and B cells must come together in the lymph node.
Cytokines play no role in B cell proliferation and differentiation.
Cytokines play no role in B cell proliferation and differentiation.
B cells can act as excellent phagocytes and antigen presenting cells (APCs).
B cells can act as excellent phagocytes and antigen presenting cells (APCs).
The up-regulation of CD40L on T cells is crucial for binding to CD40 on B cells.
The up-regulation of CD40L on T cells is crucial for binding to CD40 on B cells.
Peptides are presented on MHC class I during B cell activation.
Peptides are presented on MHC class I during B cell activation.
Signal 1 of B cell activation comes from BCR recognizing antigen.
Signal 1 of B cell activation comes from BCR recognizing antigen.
Priming of naïve B cells occurs through T cell recognition alone.
Priming of naïve B cells occurs through T cell recognition alone.
The antigen binding site can recognize and bind to an antigen very tightly.
The antigen binding site can recognize and bind to an antigen very tightly.
The antigen binding site can only recognize identical epitopes.
The antigen binding site can only recognize identical epitopes.
The complement binding site is where C1q protein binds to initiate the classical complement cascade.
The complement binding site is where C1q protein binds to initiate the classical complement cascade.
The complement binding site is responsible for binding antigens.
The complement binding site is responsible for binding antigens.
Epitopes are unrecognizable by the antigen binding site.
Epitopes are unrecognizable by the antigen binding site.
Isotype switching allows B cells to produce different antibody isoforms such as IgM, IgG, and IgA.
Isotype switching allows B cells to produce different antibody isoforms such as IgM, IgG, and IgA.
Affinity maturation leads to a decrease in the affinity of antibodies with repeated exposure to an antigen.
Affinity maturation leads to a decrease in the affinity of antibodies with repeated exposure to an antigen.
The process of isotype switching involves the replacement of the heavy chain's constant region.
The process of isotype switching involves the replacement of the heavy chain's constant region.
Macrophages and NK cells do not have Fc binding sites.
Macrophages and NK cells do not have Fc binding sites.
Cytokines released by T helper cells are not involved in isotype switching.
Cytokines released by T helper cells are not involved in isotype switching.
When B cells undergo affinity maturation, random mutations create various B cell clones of differing affinities.
When B cells undergo affinity maturation, random mutations create various B cell clones of differing affinities.
IgM is the last antibody secreted during an immune response.
IgM is the last antibody secreted during an immune response.
Isotype switching retains the original antigen binding specificity.
Isotype switching retains the original antigen binding specificity.
Basophils are not considered immune cells with Fc binding sites.
Basophils are not considered immune cells with Fc binding sites.
The affinity of antibodies decreases with limiting amounts of antibody during affinity maturation.
The affinity of antibodies decreases with limiting amounts of antibody during affinity maturation.
B cells are part of the adaptive immune system.
B cells are part of the adaptive immune system.
B cells primarily combat intracellular pathogens.
B cells primarily combat intracellular pathogens.
Every B cell has a unique B cell receptor (BCR).
Every B cell has a unique B cell receptor (BCR).
Antibodies produced by plasma cells are secreted into the lymphatic system only.
Antibodies produced by plasma cells are secreted into the lymphatic system only.
B cells can recognize antigens in various biological forms.
B cells can recognize antigens in various biological forms.
Upon activation, B cells do not proliferate and differentiate.
Upon activation, B cells do not proliferate and differentiate.
Isotype class switching is a process related to B cell function.
Isotype class switching is a process related to B cell function.
IgG is the only antibody class that can cross the placenta.
IgG is the only antibody class that can cross the placenta.
Plasma cells do not produce antibodies.
Plasma cells do not produce antibodies.
IgE antibodies are primarily involved in neutralizing toxins and microbes.
IgE antibodies are primarily involved in neutralizing toxins and microbes.
The process of affinity maturation occurs after B cell activation.
The process of affinity maturation occurs after B cell activation.
B cell deficiencies are unrelated to any diseases.
B cell deficiencies are unrelated to any diseases.
Antibodies can opsonize microbes to make them more recognizable for phagocytes.
Antibodies can opsonize microbes to make them more recognizable for phagocytes.
The Fc region of antibodies is required for neutralization.
The Fc region of antibodies is required for neutralization.
B cells produce immunoglobulins, commonly known as antibodies.
B cells produce immunoglobulins, commonly known as antibodies.
Antigen recognition leads to B cell inactivation.
Antigen recognition leads to B cell inactivation.
Natural Killer cells utilize IgM antibodies to recognize and destroy target cells.
Natural Killer cells utilize IgM antibodies to recognize and destroy target cells.
IgA antibodies are secreted at mucosal surfaces.
IgA antibodies are secreted at mucosal surfaces.
B cells develop through a series of stages including receptor rearrangement.
B cells develop through a series of stages including receptor rearrangement.
Complements can only be activated by IgM antibodies.
Complements can only be activated by IgM antibodies.
The primary role of B cells is to serve as memory cells.
The primary role of B cells is to serve as memory cells.
Phagocytes have Fcg receptors that allow them to recognize IgG coated pathogens.
Phagocytes have Fcg receptors that allow them to recognize IgG coated pathogens.
IgD antibodies have a well-understood function in the immune response.
IgD antibodies have a well-understood function in the immune response.
Antibody-dependent cellular cytotoxicity involves the killing of antibody-coated cells by NK cells.
Antibody-dependent cellular cytotoxicity involves the killing of antibody-coated cells by NK cells.
Most helminths can easily be phagocytosed by antibodies.
Most helminths can easily be phagocytosed by antibodies.
IgG is the most abundant antibody in the body.
IgG is the most abundant antibody in the body.
Opsonization involves marking a pathogen for ingestion and destruction.
Opsonization involves marking a pathogen for ingestion and destruction.
IgM is the first antibody to be secreted upon initial exposure to an antigen.
IgM is the first antibody to be secreted upon initial exposure to an antigen.
The antigen binding site can distinguish between very similar epitopes.
The antigen binding site can distinguish between very similar epitopes.
C1q protein binds at the antigen binding site to initiate the classical complement cascade.
C1q protein binds at the antigen binding site to initiate the classical complement cascade.
The complement binding site is specific for particular antigens.
The complement binding site is specific for particular antigens.
B cell activation requires two steps and not three.
B cell activation requires two steps and not three.
The antigen binding site binds loosely to antigens.
The antigen binding site binds loosely to antigens.
B cells can generate memory cells after activation.
B cells can generate memory cells after activation.
The complement binding site is associated with starting the classical complement cascade process.
The complement binding site is associated with starting the classical complement cascade process.
The interaction between CD40 on B cells and CD40L on T helper cells is important for B cell activation.
The interaction between CD40 on B cells and CD40L on T helper cells is important for B cell activation.
B cells only respond to antigens that are free and do not require presentation by other cells.
B cells only respond to antigens that are free and do not require presentation by other cells.
B cells mainly mature in the thymus.
B cells mainly mature in the thymus.
B cells are removed by negative selection if they bind to self-peptide too tightly.
B cells are removed by negative selection if they bind to self-peptide too tightly.
B cell activation can occur with just the binding of an antigen to the B cell receptor (BCR).
B cell activation can occur with just the binding of an antigen to the B cell receptor (BCR).
The CD4 T cell does not need to be fully activated for B cells to function effectively.
The CD4 T cell does not need to be fully activated for B cells to function effectively.
Activated T helper cells do not recognize antigens presented by B cells.
Activated T helper cells do not recognize antigens presented by B cells.
Cytokines produced by T cells have no influence on B cell proliferation and differentiation.
Cytokines produced by T cells have no influence on B cell proliferation and differentiation.
Naïve B cells are primed through both BCR recognition and MHC class II recognition.
Naïve B cells are primed through both BCR recognition and MHC class II recognition.
B cells are excellent at phagocytosis and can act as antigen presenting cells.
B cells are excellent at phagocytosis and can act as antigen presenting cells.
The up-regulation of CD40 on B cells is necessary for the binding of activated T helper cells.
The up-regulation of CD40 on B cells is necessary for the binding of activated T helper cells.
Mutations that occur during affinity maturation decrease the affinity of antibodies.
Mutations that occur during affinity maturation decrease the affinity of antibodies.
IgG is the most abundant antibody isotype found in serum and can perform all known antibody functions.
IgG is the most abundant antibody isotype found in serum and can perform all known antibody functions.
The Fc region of an antibody is primarily responsible for neutralizing pathogens.
The Fc region of an antibody is primarily responsible for neutralizing pathogens.
Selective IgA deficiency is the least common form of immunodeficiency.
Selective IgA deficiency is the least common form of immunodeficiency.
X-linked agammaglobulinemia (XLA) results in absent B cells due to a mutation in a protein involved in B cell development.
X-linked agammaglobulinemia (XLA) results in absent B cells due to a mutation in a protein involved in B cell development.
IgM is completely ineffective in opsonization.
IgM is completely ineffective in opsonization.
Individuals with Common Variable Immune Deficiency (CVID) usually have normal levels of IgG, IgM, and IgA.
Individuals with Common Variable Immune Deficiency (CVID) usually have normal levels of IgG, IgM, and IgA.
B cells are characterized by their ability to produce only IgA antibodies.
B cells are characterized by their ability to produce only IgA antibodies.
The majority of patients with selective IgA deficiency are asymptomatic due to adequate levels of IgM.
The majority of patients with selective IgA deficiency are asymptomatic due to adequate levels of IgM.
B cells can recognize antigens in various biological forms including proteins, carbohydrates, and lipids.
B cells can recognize antigens in various biological forms including proteins, carbohydrates, and lipids.
Plasma cells are responsible for producing antibodies after B cell activation.
Plasma cells are responsible for producing antibodies after B cell activation.
Affinity maturation results in a decreased affinity of antibodies after repeated exposure to an antigen.
Affinity maturation results in a decreased affinity of antibodies after repeated exposure to an antigen.
Isotype class switching allows B cells to produce antibodies with different specificities.
Isotype class switching allows B cells to produce antibodies with different specificities.
Cytokines released by T helper cells play a critical role in B cell activation and differentiation.
Cytokines released by T helper cells play a critical role in B cell activation and differentiation.
Each B cell produces a unique B cell receptor that can recognize a specific antigen.
Each B cell produces a unique B cell receptor that can recognize a specific antigen.
Immunoglobulin (Ig) is another term for antibodies.
Immunoglobulin (Ig) is another term for antibodies.
The constant region of an antibody is mainly responsible for binding to antigens.
The constant region of an antibody is mainly responsible for binding to antigens.
B cell activation only requires signals from T helper cells.
B cell activation only requires signals from T helper cells.
Antibodies produced are secreted into circulation but not into mucus membranes.
Antibodies produced are secreted into circulation but not into mucus membranes.
Antigen recognition causes B cells to proliferate and differentiate.
Antigen recognition causes B cells to proliferate and differentiate.
B cell deficiencies can be associated with various diseases.
B cell deficiencies can be associated with various diseases.
IgG antibodies are the only class that can cross the placenta.
IgG antibodies are the only class that can cross the placenta.
The Fc region of antibodies is crucial for their ability to neutralize pathogens.
The Fc region of antibodies is crucial for their ability to neutralize pathogens.
IgE antibodies are primarily implicated in mediating reactions against helminths.
IgE antibodies are primarily implicated in mediating reactions against helminths.
Opsonisation is the process where antibodies make pathogens difficult for phagocytes to recognize.
Opsonisation is the process where antibodies make pathogens difficult for phagocytes to recognize.
IgG is the most abundant antibody class in the body and is involved in all antibody functions.
IgG is the most abundant antibody class in the body and is involved in all antibody functions.
Complement activation requires only the antigen-binding site of antibodies.
Complement activation requires only the antigen-binding site of antibodies.
Natural Killer cells utilize FcγRIII receptors to recognize IgM attached to target cells.
Natural Killer cells utilize FcγRIII receptors to recognize IgM attached to target cells.
The primary function of the Fc region of an antibody is to neutralize toxins.
The primary function of the Fc region of an antibody is to neutralize toxins.
Antibody-dependent cellular cytotoxicity involves the destruction of antibody-coated cells by natural killer cells.
Antibody-dependent cellular cytotoxicity involves the destruction of antibody-coated cells by natural killer cells.
IgA is primarily secreted at mucosal surfaces and plays a role in neutralizing pathogens.
IgA is primarily secreted at mucosal surfaces and plays a role in neutralizing pathogens.
Phagocytes can recognize opsonized microbes through specific receptors for IgM.
Phagocytes can recognize opsonized microbes through specific receptors for IgM.
IgM is the first antibody to be secreted during an immune response and is involved in complement activation.
IgM is the first antibody to be secreted during an immune response and is involved in complement activation.
Eosinophils and mast cells express Fcε receptors for IgG antibodies.
Eosinophils and mast cells express Fcε receptors for IgG antibodies.
The main function of antibodies is to phagocytose pathogens directly.
The main function of antibodies is to phagocytose pathogens directly.
The presence of IgD is primarily associated with the surface of naïve B cells and its role is unclear.
The presence of IgD is primarily associated with the surface of naïve B cells and its role is unclear.
Antibodies can only protect against extracellular pathogens.
Antibodies can only protect against extracellular pathogens.
The primary site of B cell maturation occurs in the lung tissues.
The primary site of B cell maturation occurs in the lung tissues.
B cell activation involves a minimum of three distinct signals to fully activate.
B cell activation involves a minimum of three distinct signals to fully activate.
The interaction between CD40L on T cells and CD40 on B cells is essential for effective B cell activation.
The interaction between CD40L on T cells and CD40 on B cells is essential for effective B cell activation.
B cells can generate memory cells after their activation.
B cells can generate memory cells after their activation.
Peptide antigens are always recognized directly by B cells without the need for T helper cells.
Peptide antigens are always recognized directly by B cells without the need for T helper cells.
The variable region of the B cell receptor (BCR) is responsible for binding to antigens.
The variable region of the B cell receptor (BCR) is responsible for binding to antigens.
A membrane bound IgM receptor is commonly referred to as the B cell co-receptor.
A membrane bound IgM receptor is commonly referred to as the B cell co-receptor.
Each B cell receptor (BCR) is identical on every B cell in an individual.
Each B cell receptor (BCR) is identical on every B cell in an individual.
B cells primarily mature in the secondary lymph organs.
B cells primarily mature in the secondary lymph organs.
In B cell development, the heavy and light chains of immunoglobulin are linked by hydrogen bonds.
In B cell development, the heavy and light chains of immunoglobulin are linked by hydrogen bonds.
The process of affinity maturation results in B cells that bind antigens less effectively over time.
The process of affinity maturation results in B cells that bind antigens less effectively over time.
Different isotypes of antibodies result from changes in the constant region of the heavy chain.
Different isotypes of antibodies result from changes in the constant region of the heavy chain.
Cytokines released by T cells have no impact on B cell proliferation.
Cytokines released by T cells have no impact on B cell proliferation.
The complement binding site is involved in the recognition of antigens.
The complement binding site is involved in the recognition of antigens.
The antigen binding site is known for its low affinity binding to antigens.
The antigen binding site is known for its low affinity binding to antigens.
C1q protein binding occurs at the complement binding site to activate the alternative complement cascade.
C1q protein binding occurs at the complement binding site to activate the alternative complement cascade.
The complement binding site specifically recognizes and binds antibodies.
The complement binding site specifically recognizes and binds antibodies.
VDJ recombination allows for the creation of approximately $10^{11}$ different B cell receptors.
VDJ recombination allows for the creation of approximately $10^{11}$ different B cell receptors.
Immature B cells express both IgM and IgD receptors.
Immature B cells express both IgM and IgD receptors.
Mature B cells are primarily developed in the spleen.
Mature B cells are primarily developed in the spleen.
Positive selection occurs when developing B cells successfully express a complete BCR.
Positive selection occurs when developing B cells successfully express a complete BCR.
BCR gene rearrangement is also known as isotype switching.
BCR gene rearrangement is also known as isotype switching.
B cell activation requires at least two signals, one of which involves T cell interaction.
B cell activation requires at least two signals, one of which involves T cell interaction.
Checkpoints during B cell development are crucial for ensuring the proliferation of B cells without significant selection.
Checkpoints during B cell development are crucial for ensuring the proliferation of B cells without significant selection.
Mature B cells do not circulate in the lymphatic system.
Mature B cells do not circulate in the lymphatic system.
Epitopes can consist of proteins, carbohydrates, and lipids, but not polysaccharides.
Epitopes can consist of proteins, carbohydrates, and lipids, but not polysaccharides.
The variable region of an antibody is responsible for activating effector responses.
The variable region of an antibody is responsible for activating effector responses.
The Fab portion of an antibody is involved in binding to the antigen and not for effector activation.
The Fab portion of an antibody is involved in binding to the antigen and not for effector activation.
Antibodies have a single constant region type that defines their entire function.
Antibodies have a single constant region type that defines their entire function.
The antigen binding site of antibodies can recognize and bind to multiple different epitopes.
The antigen binding site of antibodies can recognize and bind to multiple different epitopes.
The complement proteins are activated by the variable region of an antibody.
The complement proteins are activated by the variable region of an antibody.
An antibody's isotype is determined by its variable region.
An antibody's isotype is determined by its variable region.
All biological molecules can serve as epitopes for antibodies.
All biological molecules can serve as epitopes for antibodies.
B cell activation requires two signals, one from the BCR and another from T helper cells.
B cell activation requires two signals, one from the BCR and another from T helper cells.
Isotype class switching results in B cells producing only one type of antibody throughout the immune response.
Isotype class switching results in B cells producing only one type of antibody throughout the immune response.
Plasma cells are short-lived cells that produce antibodies.
Plasma cells are short-lived cells that produce antibodies.
Affinity maturation occurs during B cell activation and enhances the binding strength of antibodies to antigens.
Affinity maturation occurs during B cell activation and enhances the binding strength of antibodies to antigens.
Each B cell has a distinct B cell receptor (BCR) that can recognize only one specific antigen.
Each B cell has a distinct B cell receptor (BCR) that can recognize only one specific antigen.
B cells can recognize antigens exclusively in protein form.
B cells can recognize antigens exclusively in protein form.
IgE is primarily involved in combating parasitic infections and allergic reactions.
IgE is primarily involved in combating parasitic infections and allergic reactions.
Cytokines released by T helper cells are necessary for the process of affinity maturation.
Cytokines released by T helper cells are necessary for the process of affinity maturation.
B cells cannot present antigens to T cells.
B cells cannot present antigens to T cells.
BCR rearrangement is an important step in B cell development.
BCR rearrangement is an important step in B cell development.
Antibodies are secreted by B cells directly into the bloodstream and can move freely across tissues.
Antibodies are secreted by B cells directly into the bloodstream and can move freely across tissues.
Basophils possess receptors for binding to the Fc region of antibodies.
Basophils possess receptors for binding to the Fc region of antibodies.
IgM is the first antibody produced in response to an infection.
IgM is the first antibody produced in response to an infection.
Flashcards
B cell role
B cell role
B cells are part of the adaptive immune system, producing antibodies to fight pathogens, mainly those outside cells.
B cell receptor (BCR)
B cell receptor (BCR)
A unique receptor on each B cell that recognizes specific antigens in different forms (protein, carbohydrate, lipid, polysaccharide).
Antigen recognition
Antigen recognition
B cells become activated when their BCR recognizes a specific antigen.
Plasma cell
Plasma cell
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Antibody (Immunoglobulin)
Antibody (Immunoglobulin)
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B cell activation
B cell activation
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Adaptive immune system
Adaptive immune system
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Effector response
Effector response
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Origin of B cells
Origin of B cells
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Negative Selection of B Cells
Negative Selection of B Cells
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B cell activation signal 1
B cell activation signal 1
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B cell activation signal 2
B cell activation signal 2
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BCR
BCR
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Self-antigen
Self-antigen
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MHC class II
MHC class II
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T helper cell
T helper cell
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Antigen Presentation
Antigen Presentation
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Phagocytosis
Phagocytosis
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Antibody structure
Antibody structure
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Epitopes
Epitopes
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Variable region
Variable region
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Constant region
Constant region
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Antigen
Antigen
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Antibody isotype
Antibody isotype
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Fab fragment
Fab fragment
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What's an epitope ?
What's an epitope ?
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Antigen Binding Site
Antigen Binding Site
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Specificity of Antigen Binding Site
Specificity of Antigen Binding Site
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Complement Binding Site
Complement Binding Site
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Classical Complement Cascade
Classical Complement Cascade
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Isotype Switching
Isotype Switching
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What is the first antibody secreted upon infection?
What is the first antibody secreted upon infection?
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What is the purpose of isotype switching?
What is the purpose of isotype switching?
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How does isotype switching affect the antigen binding site?
How does isotype switching affect the antigen binding site?
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What initiates isotype switching?
What initiates isotype switching?
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Affinity Maturation
Affinity Maturation
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How does affinity maturation improve antibody effectiveness?
How does affinity maturation improve antibody effectiveness?
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How does affinity maturation occur?
How does affinity maturation occur?
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Antibody effector functions
Antibody effector functions
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Antibody Neutralization
Antibody Neutralization
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Opsonization
Opsonization
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Complement Activation
Complement Activation
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Antibody-Dependent Cellular Cytotoxicity (ADCC)
Antibody-Dependent Cellular Cytotoxicity (ADCC)
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Eosinophil/Mast Cell-Mediated Reactions
Eosinophil/Mast Cell-Mediated Reactions
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What is neutralization?
What is neutralization?
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What is opsonization?
What is opsonization?
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What is complement activation?
What is complement activation?
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What is antibody-dependent cellular cytotoxicity (ADCC)?
What is antibody-dependent cellular cytotoxicity (ADCC)?
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What are eosinophil/mast cell-mediated reactions?
What are eosinophil/mast cell-mediated reactions?
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What is the B cell receptor (BCR)?
What is the B cell receptor (BCR)?
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Why do B cells become activated?
Why do B cells become activated?
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Plasma cell function
Plasma cell function
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What is an antibody?
What is an antibody?
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Why are B cells important in the adaptive immune response?
Why are B cells important in the adaptive immune response?
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What is isotype switching?
What is isotype switching?
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What does affinity maturation do?
What does affinity maturation do?
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What is antibody neutralization?
What is antibody neutralization?
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What is the complement system?
What is the complement system?
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What makes B cells unique?
What makes B cells unique?
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What is B cell activation?
What is B cell activation?
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What makes a plasma cell special?
What makes a plasma cell special?
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What are memory B cells?
What are memory B cells?
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What are the main types of antibodies?
What are the main types of antibodies?
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What initiates the complement pathway?
What initiates the complement pathway?
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Most abundant antibody in serum
Most abundant antibody in serum
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IgG functions
IgG functions
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Antibody region for neutralization
Antibody region for neutralization
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Common Variable Immune Deficiency (CVID)
Common Variable Immune Deficiency (CVID)
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Selective IgA Deficiency
Selective IgA Deficiency
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X-linked agammaglobulinemia (XLA)
X-linked agammaglobulinemia (XLA)
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Why is antibody neutralization important?
Why is antibody neutralization important?
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What is the significance of the Fc region?
What is the significance of the Fc region?
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Neutralization
Neutralization
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How Does Neutralization Protect Against Infection?
How Does Neutralization Protect Against Infection?
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What is the Role of Opsonization in Phagocytosis?
What is the Role of Opsonization in Phagocytosis?
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How Does Complement Activation Contribute to Immune Defense?
How Does Complement Activation Contribute to Immune Defense?
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What is the Mechanism of Antibody-Dependent Cellular Cytotoxicity (ADCC)?
What is the Mechanism of Antibody-Dependent Cellular Cytotoxicity (ADCC)?
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What is the role of CD40 and CD40L?
What is the role of CD40 and CD40L?
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How do B cells get activated?
How do B cells get activated?
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What do cytokines do for B cells?
What do cytokines do for B cells?
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What are MHC Class II molecules?
What are MHC Class II molecules?
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What is the role of T helper cells in B cell activation?
What is the role of T helper cells in B cell activation?
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What is the difference between naïve and activated B cells?
What is the difference between naïve and activated B cells?
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What is the significance of B cells being excellent phagocytes?
What is the significance of B cells being excellent phagocytes?
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B cell development
B cell development
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Memory B cells
Memory B cells
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B cell maturation
B cell maturation
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B cell antigen specificity
B cell antigen specificity
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What does CD40 do for B cells?
What does CD40 do for B cells?
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B cell activation steps
B cell activation steps
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B cell
B cell
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Antibody
Antibody
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B cell diversity
B cell diversity
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VDJ recombination
VDJ recombination
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B cell development checkpoints
B cell development checkpoints
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Positive selection of B cells
Positive selection of B cells
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Mature B cell
Mature B cell
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What are antibodies?
What are antibodies?
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Antibody function
Antibody function
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What is the constant region of an antibody?
What is the constant region of an antibody?
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What are antibody isotypes?
What are antibody isotypes?
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Why are variable regions important?
Why are variable regions important?
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Study Notes
Adaptive Immunity - B Cells
- B cells are part of the adaptive immune system, specifically targeting antigens.
- They produce antibodies, critical in fighting pathogens, particularly extracellular ones.
- B cells have unique B cell receptors (BCRs).
- BCRs recognize antigens in various forms (proteins, carbohydrates, lipids, polysaccharides).
- Antigen recognition activates B cells, causing proliferation and differentiation into plasma cells.
- Each plasma cell produces trillions of antibodies (immunoglobulins).
- Antibodies are released into the bloodstream and mucous membranes, triggering responses.
Lecture Learning Outcomes
- Students should be able to outline the roles of B cells in the adaptive immune response.
- They should be able to describe B cell development, including receptor rearrangement.
- Students should be able to describe steps in B cell activation.
- Understanding isotype class switching and affinity maturation is crucial.
- Comparing and contrasting different antibody classes is essential.
- Describing antibody structure and effector functions is necessary.
- Listing diseases associated with B cell deficiencies is expected.
Key Roles of B Cells
- B cells are adaptive immune system cells that recognize specific antigens.
- They primarily produce antibodies crucial for attacking extracellular pathogens.
- B cells interact with multiple parts of the immune system, including phagocytes, cytotoxic cells, etc.
Key Roles of B Cells (Detailed)
- Each B cell has a unique B cell receptor (BCR).
- BCRs recognize antigens (proteins, carbohydrates, lipids, polysaccharides).
- Antigens activate B cells, causing proliferation and maturation to plasma cells.
- Plasma cells produce vast quantities of antibodies.
- Antibodies circulate and prevent pathogen entry via binding to pathogens and toxins.
Pertinent Questions
- Where do B cells originate?
- What are the key stages of B cell development?
- How do B cells acquire unique BCRs?
- How do antibodies function?
B Cell Development
- B cell development occurs in primary and secondary lymph organs.
- Primary involves generative lymphoid organs (e.g., bone marrow).
- A primary stage results in immature B cells acquiring BCRs.
- This is followed by a secondary process where B cells acquire other receptors.
- Mature B cells circulate in peripheral lymphoid organs (e.g., spleen, lymph nodes).
Membrane IgM Receptor (BCR)
- A membrane-bound IgM is a B cell receptor.
- It's composed of four polypeptide chains (two heavy and two light chains).
- Heavy and light chains are joined by disulfide bonds.
- It's structured like a 'Y' and has variable and constant regions.
Creating B Cells to Respond to All Possible Antigens
- B cells have millions of different BCRs.
- BCR diversity is achieved via V(D)J recombination of genes that form BCRs.
- This process randomly combines V, D, and J gene segments.
- This results in an immense array of BCR possibilities (10^11).
B Cell Development Checkpoints
- B cell development has checkpoints to ensure BCR function and prevent self-reactivity.
- Positive selection: Check if BCRs are functional, ensuring survival of cells with correctly functioning BCRs.
- Negative selection: Check for self-reactivity, eliminating cells that bind too strongly to self-peptides.
Naïve B Cells
- Naïve B cells leave the bone marrow with a functional BCR, ready for antigen encounter.
B Cell Activation
- B cell activation needs two signals; the first is antigen binding to the BCR.
- The second is receiving signals from helper T cells.
B Cells and T Cells Working Together
- B cells and T cells work together in lymph nodes.
- Helper T cells are activated when they recognize the antigen presentation.
- Activated helper T cells interact with activated B cells, promoting B cell proliferation, differentiation, and isotype switching.
Signal 2 - T Helper Cell Help
- Activated helper T cells express CD40L to bind to CD40 on B cells.
- T cells also secrete cytokines that stimulate B cell proliferation and differentiation into plasma cells.
- These factors are important for driving antibody production and variety of antibodies.
Antibody Effector Functions
- Antibodies facilitate various functions protecting the body from foreign invaders.
- Some examples include neutralization, complement activation, and antibody-dependent cellular cytotoxicity.
Antibody Neutralization
- Antibodies bind to pathogens or toxins, neutralizing their activity.
- This prevents pathogens from infecting cells and toxins damaging cells.
Opsonization & Phagocytosis
- Antibodies coat pathogens (opsonization).
- Phagocytes recognize and engulf antibody-coated pathogens, destroying them.
Complement Activation
- Antibodies activate the complement system.
- This results in a cascade of events.
- The activation causes inflammation, phagocytosis, or lysis of pathogens.
Antibody-Dependent Cellular Cytotoxicity
- Antibody-coated cells activate immune cells (e.g., NK cells).
- These immune cells kill the antibody-coated pathogens.
Eosinophil/Mast Cell-Mediated Reactions
- Specific antibodies (e.g., IgE) trigger eosinophils or mast cells.
- These cells release granules that destroy parasitic worms.
- IgE is the primary antibody in allergic and worm-infections.
Antigen and Antibody Classes
- Antibodies and their functions vary based on their type, determined by their heavy chain type (e.g. IgG, IgA, IgE, etc.).
- Different heavy chain types have unique roles and structures of each type.
Isotype Switching and Affinity Maturation
- B cells can switch antibody isotypes (e.g., from IgM to IgG).
- This change is driven by signals from helper T cells, facilitating specialized function depending on the pathogen or infection.
- Affinity maturation increases antibody binding strength via mutations in the variable region.
B Cell/Antibody Deficiencies
- Common Variable Immunodeficiency (CVID) is characterized by low antibody levels.
- Selective IgA deficiency is the most common immunodeficiency, characterized by failure to produce IgA antibodies.
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Description
This quiz explores the roles and functions of B cells in the adaptive immune system. It covers antibody production, B cell receptor activation, and the steps involved in B cell development and differentiation. Understanding these concepts is essential for comprehending the adaptive immune response to pathogens.
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