Podcast
Questions and Answers
What are antibodies?
What are antibodies?
- Antigen-binding proteins present on the B-cell membrane and secreted by plasma cells (correct)
- Proteins that directly attack antigens
- Proteins present on T-cell membrane and secreted by plasma cells
- Proteins only present on the B-cell membrane
How does the immune system usually respond to complex antigens?
How does the immune system usually respond to complex antigens?
- By producing a single antibody for the entire antigen
- By activating T cells instead of producing antibodies
- By producing antibodies to several epitopes on the antigen (correct)
- By producing antibodies to only one epitope on the antigen
What are the outputs of B cells in response to complex antigens?
What are the outputs of B cells in response to complex antigens?
- Polyclonal antibodies, each binding multiple antigenic determinants
- Monoclonal antibodies, each binding multiple antigenic determinants
- Monoclonal antibodies, each specifically binding a single antigenic determinant (correct)
- Polyclonal antibodies, each specifically binding a single antigenic determinant
Where do antibodies reside?
Where do antibodies reside?
What are antibodies also commonly referred to as?
What are antibodies also commonly referred to as?
Which fraction of the blood contains red blood cells, leukocytes, and platelets?
Which fraction of the blood contains red blood cells, leukocytes, and platelets?
What is the common structure of antibody molecules?
What is the common structure of antibody molecules?
What type of chains make up the structure of antibody molecules?
What type of chains make up the structure of antibody molecules?
How many peptide chains make up the structure of antibody molecules?
How many peptide chains make up the structure of antibody molecules?
What type of bond links each light chain to a heavy chain in the antibody structure?
What type of bond links each light chain to a heavy chain in the antibody structure?
What gives segmental flexibility to the immunoglobulin?
What gives segmental flexibility to the immunoglobulin?
What forms the basic four-chain antibody structure?
What forms the basic four-chain antibody structure?
What is the composition of the antigen-binding site of the antibody molecule?
What is the composition of the antigen-binding site of the antibody molecule?
Which region of the immunoglobulin molecule differs from one antibody to another?
Which region of the immunoglobulin molecule differs from one antibody to another?
How many amino acids typically make up the amino-terminal variable (V) region in each heavy and light chain of an immunoglobulin molecule?
How many amino acids typically make up the amino-terminal variable (V) region in each heavy and light chain of an immunoglobulin molecule?
What is the composition of the constant (C) region in heavy chain of an antibody molecule?
What is the composition of the constant (C) region in heavy chain of an antibody molecule?
Which region of the antibody molecule mediates most of the biological functions of antibodies?
Which region of the antibody molecule mediates most of the biological functions of antibodies?
Where are the membrane-bound antibodies in the plasma membranes of B lymphocytes attached?
Where are the membrane-bound antibodies in the plasma membranes of B lymphocytes attached?
How many sub isotypes of α heavy chains are there in humans?
How many sub isotypes of α heavy chains are there in humans?
How many distinct classes and subclasses can antibody molecules be divided into based on differences in the structure of their heavy constant chain (HC) regions?
How many distinct classes and subclasses can antibody molecules be divided into based on differences in the structure of their heavy constant chain (HC) regions?
How many sub isotypes of ϒ heavy chains are there in humans?
How many sub isotypes of ϒ heavy chains are there in humans?
What do hypervariable regions correspond to in antibody-antigen interaction?
What do hypervariable regions correspond to in antibody-antigen interaction?
Where do smaller antigens fit in the variable regions of antibodies?
Where do smaller antigens fit in the variable regions of antibodies?
How do larger antigens interact with the variable region of antibodies?
How do larger antigens interact with the variable region of antibodies?
What is opsonization?
What is opsonization?
What initiates the signal-transduction pathway resulting in the phagocytosis of the antigen-antibody complex?
What initiates the signal-transduction pathway resulting in the phagocytosis of the antigen-antibody complex?
What are protein molecules called that can bind the constant region of Ig molecules and are present on the surfaces of macrophages and neutrophils?
What are protein molecules called that can bind the constant region of Ig molecules and are present on the surfaces of macrophages and neutrophils?
Which immunoglobulin subclasses can activate the complement system in humans?
Which immunoglobulin subclasses can activate the complement system in humans?
What is the protein fragment produced as an important byproduct of the complement activation pathway?
What is the protein fragment produced as an important byproduct of the complement activation pathway?
What allows erythrocytes to deliver antigen-antibody complexes to the liver or spleen for removal?
What allows erythrocytes to deliver antigen-antibody complexes to the liver or spleen for removal?
Which cell type can direct the cytotoxic activities against target cells in antibody-dependent cell-mediated cytotoxicity (ADCC)?
Which cell type can direct the cytotoxic activities against target cells in antibody-dependent cell-mediated cytotoxicity (ADCC)?
What is the role of the antibody in antibody-dependent cell-mediated cytotoxicity (ADCC)?
What is the role of the antibody in antibody-dependent cell-mediated cytotoxicity (ADCC)?
What type of cells have Fc receptors that can link with antibody bound to target cells in antibody-dependent cell-mediated cytotoxicity (ADCC)?
What type of cells have Fc receptors that can link with antibody bound to target cells in antibody-dependent cell-mediated cytotoxicity (ADCC)?
Which process is responsible for the movement of immunoglobulin across epithelial layers?
Which process is responsible for the movement of immunoglobulin across epithelial layers?
Which antibody species is the major one that undergoes transcytosis in humans and mice?
Which antibody species is the major one that undergoes transcytosis in humans and mice?
What type of transcytosis is a form of passive immunization?
What type of transcytosis is a form of passive immunization?
What is the main function of Fc receptors (FcR) in relation to antibodies?
What is the main function of Fc receptors (FcR) in relation to antibodies?
Which cell types can passively acquire antibodies through Fc receptors?
Which cell types can passively acquire antibodies through Fc receptors?
What is the specific affinity of Fc receptors (FcR) in relation to the antibody molecule?
What is the specific affinity of Fc receptors (FcR) in relation to the antibody molecule?
Which IgG subclass readily crosses the placenta and plays a role in protecting the developing fetus?
Which IgG subclass readily crosses the placenta and plays a role in protecting the developing fetus?
Which IgG subclass is the most effective complement activator?
Which IgG subclass is the most effective complement activator?
Which IgG subclass binds with high affinity to Fc receptors on phagocytic cells and mediates opsonization?
Which IgG subclass binds with high affinity to Fc receptors on phagocytic cells and mediates opsonization?
Is IgG the most abundant class in serum, constituting about 80% of the total serum immunoglobulin?
Is IgG the most abundant class in serum, constituting about 80% of the total serum immunoglobulin?
Do IgG1, IgG3, and IgG4 readily cross the placenta and play an important role in protecting the developing fetus?
Do IgG1, IgG3, and IgG4 readily cross the placenta and play an important role in protecting the developing fetus?
Is IgG4 able to activate complement at all?
Is IgG4 able to activate complement at all?
Is IgM the first immunoglobulin class produced in a primary response to an antigen?
Is IgM the first immunoglobulin class produced in a primary response to an antigen?
Does IgM have a higher valency than the other isotypes due to its pentameric structure with 10 antigen-binding sites?
Does IgM have a higher valency than the other isotypes due to its pentameric structure with 10 antigen-binding sites?
Is IgM the first immunoglobulin to be synthesized by the neonate?
Is IgM the first immunoglobulin to be synthesized by the neonate?
Is IgM more efficient than IgG at activating complement?
Is IgM more efficient than IgG at activating complement?
Is IgM found in very low concentrations in the intercellular tissue fluids due to its large size?
Is IgM found in very low concentrations in the intercellular tissue fluids due to its large size?
Does IgM require less IgM than IgG to neutralize viral infectivity?
Does IgM require less IgM than IgG to neutralize viral infectivity?
Where is Immunoglobulin A (IgA) predominantly found?
Where is Immunoglobulin A (IgA) predominantly found?
What is the daily production of secretory IgA compared to other immunoglobulin classes?
What is the daily production of secretory IgA compared to other immunoglobulin classes?
Where are IgA-secreting plasma cells concentrated?
Where are IgA-secreting plasma cells concentrated?
What prevents the attachment of pathogens to mucosal cells?
What prevents the attachment of pathogens to mucosal cells?
What does breast milk contain that helps protect newborns against infection?
What does breast milk contain that helps protect newborns against infection?
Which molecule in breast milk plays a key role in protecting newborns against infection?
Which molecule in breast milk plays a key role in protecting newborns against infection?
What is the role of the J chain in secretory IgA?
What is the role of the J chain in secretory IgA?
Where does secretory IgA serve an important effector function?
Where does secretory IgA serve an important effector function?
What plays an important role in maintaining the health of newborns due to the incomplete immune system of infants?
What plays an important role in maintaining the health of newborns due to the incomplete immune system of infants?
What is the main function of IgE antibodies?
What is the main function of IgE antibodies?
Where does IgE bind in the body?
Where does IgE bind in the body?
What was the basis for the first biological assay for IgE activity?
What was the basis for the first biological assay for IgE activity?
What is the main function of IgE antibodies?
What is the main function of IgE antibodies?
What does IgE bind to in the body?
What does IgE bind to in the body?
What was the basis for the first biological assay for IgE activity?
What was the basis for the first biological assay for IgE activity?
Is allergen cross-linkage of receptor-bound IgE on mast cells responsible for causing release of substances that mediate allergic manifestations?
Is allergen cross-linkage of receptor-bound IgE on mast cells responsible for causing release of substances that mediate allergic manifestations?
Does degranulation of mast cells release substances that mediate allergic manifestations?
Does degranulation of mast cells release substances that mediate allergic manifestations?
Is the release of substances (blue dots) from mast cells responsible for mediating allergic manifestations?
Is the release of substances (blue dots) from mast cells responsible for mediating allergic manifestations?
What was the basis for the discovery of Immunoglobulin D (IgD)?
What was the basis for the discovery of Immunoglobulin D (IgD)?
Which immunoglobulin is expressed as a major membrane-bound form by mature B cells?
Which immunoglobulin is expressed as a major membrane-bound form by mature B cells?
What is the current status of the role of IgD in the physiology of B cells?
What is the current status of the role of IgD in the physiology of B cells?
Which of the following is a member of the immunoglobulin superfamily?
Which of the following is a member of the immunoglobulin superfamily?
Which protein is associated with class I MHC molecules?
Which protein is associated with class I MHC molecules?
Which of the following is a T-cell accessory protein?
Which of the following is a T-cell accessory protein?
What is the composition of the B-cell receptor (BCR)?
What is the composition of the B-cell receptor (BCR)?
What is the length of the cytoplasmic tail in the Ig- α chain of the B-cell receptor (BCR)?
What is the length of the cytoplasmic tail in the Ig- α chain of the B-cell receptor (BCR)?
What is the function of the cytoplasmic tails in both Ig- α and Ig- β chains?
What is the function of the cytoplasmic tails in both Ig- α and Ig- β chains?
What are the three major categories of antigenic determinants on immunoglobulin molecules?
What are the three major categories of antigenic determinants on immunoglobulin molecules?
Where are the idiotypic determinants located in the antibody molecule?
Where are the idiotypic determinants located in the antibody molecule?
What are the three major categories of antigenic determinants on immunoglobulin molecules?
What are the three major categories of antigenic determinants on immunoglobulin molecules?
What collectively defines each heavy-chain class and subclass and each light-chain type and subtype within a species?
What collectively defines each heavy-chain class and subclass and each light-chain type and subtype within a species?
What will be recognized as foreign when an antibody from one species is injected into another species?
What will be recognized as foreign when an antibody from one species is injected into another species?
What are encoded by separate constant region genes, with all members of a species carrying the same constant-region genes?
What are encoded by separate constant region genes, with all members of a species carrying the same constant-region genes?
What are allotypic determinants?
What are allotypic determinants?
When can antibodies to allotypic determinants be produced in response to paternal allotypic determinants?
When can antibodies to allotypic determinants be produced in response to paternal allotypic determinants?
What can give rise to antibodies to allotypic determinants?
What can give rise to antibodies to allotypic determinants?
Where are idiotope sequences located?
Where are idiotope sequences located?
What is each individual antigenic determinant of the variable region referred to as?
What is each individual antigenic determinant of the variable region referred to as?
In which region may an idiotope comprise variable-region sequences outside of the antigen-binding site?
In which region may an idiotope comprise variable-region sequences outside of the antigen-binding site?
What type of differences occur in the constant region from one species to another when it comes to immunoglobulins?
What type of differences occur in the constant region from one species to another when it comes to immunoglobulins?
Which type of differences occur in the variable regions and can differ even on antibodies of the same isotype?
Which type of differences occur in the variable regions and can differ even on antibodies of the same isotype?
What term is used for the differences (alleles) that occur in some individuals with respect to immunoglobulins?
What term is used for the differences (alleles) that occur in some individuals with respect to immunoglobulins?
What type of antibodies are derived from a single clone and specific for a single epitope?
What type of antibodies are derived from a single clone and specific for a single epitope?
What is the advantage of a polyclonal antibody response for an organism in vivo?
What is the advantage of a polyclonal antibody response for an organism in vivo?
What is the primary function of monoclonal antibodies?
What is the primary function of monoclonal antibodies?
What is a hybridoma?
What is a hybridoma?
What are the properties of hybridoma cells?
What are the properties of hybridoma cells?
Why was the work by Kohler and Milstein significant?
Why was the work by Kohler and Milstein significant?
Why are monoclonal antibodies useful in clinical applications?
Why are monoclonal antibodies useful in clinical applications?
What are the clinical uses of monoclonal antibodies?
What are the clinical uses of monoclonal antibodies?
What is a key advantage of monoclonal antibodies in terms of production?
What is a key advantage of monoclonal antibodies in terms of production?
What is the target of adalimumab (Humira)?
What is the target of adalimumab (Humira)?
Which cell type is targeted by rituximab (Rituxan)?
Which cell type is targeted by rituximab (Rituxan)?
What is the term for human monoclonal antibodies drugs, indicated by the suffix (-umab)?
What is the term for human monoclonal antibodies drugs, indicated by the suffix (-umab)?
Monoclonal antibodies drugs can be indicated by the suffix (-umab)?
Monoclonal antibodies drugs can be indicated by the suffix (-umab)?
Adalimumab, known as Humira, targets TNF to reduce inflammation?
Adalimumab, known as Humira, targets TNF to reduce inflammation?
Rituximab, known as Rituxan, targets CD20 found on lymphomal B cells?
Rituximab, known as Rituxan, targets CD20 found on lymphomal B cells?
Study Notes
Antibodies and the Immune Response
- Antibodies, or immunoglobulins, are specialized proteins produced by B cells in response to antigens.
- The immune system recognizes complex antigens through B cell receptors, leading to the activation of B cells.
- B cells differentiate into plasma cells, which produce antibodies specifically targeting these antigens.
Structure and Composition of Antibodies
- Antibodies typically consist of four peptide chains, including two heavy chains and two light chains.
- Each light chain is linked to a heavy chain via disulfide bonds, contributing to a stable structure.
- The antigen-binding site comprises variable regions of both heavy and light chains, allowing specific binding to antigens.
- Heavy chains determine the antibody's class and subclass, with specific constant regions.
Biological Functions of Antibodies
- The constant region of antibodies mediates most biological functions and interacts with other immune components.
- Smaller antigens fit into the variable regions, while larger antigens engage via multiple interaction sites.
Antibody Types and Their Functions
- IgG is the most abundant antibody in serum, constituting about 80% and is crucial for opsonization and neutralization.
- IgM is produced first in responses to antigens, characterized by its pentameric structure allowing high valency (10 binding sites).
- IgA is primarily found in mucosal areas and secretions, providing barrier protection against pathogens.
Roles of IgE and IgD
- IgE is involved in allergic reactions; it binds to allergens and activates mast cells upon cross-linkage.
- IgD is present on the surface of B cells and plays a less-defined role in B cell physiology.
Antibody Subtypes and Clinical Applications
- Humans have multiple IgG subclasses (IgG1, IgG2, IgG3, IgG4) that differ in their ability to activate complement and cross the placenta.
- Monoclonal antibodies are derived from a single clone and are highly specific for one epitope, useful for targeted therapies.
Mechanisms of Antibody Function
- Antibodies can opsonize pathogens, enhancing their recognition and phagocytosis by immune cells.
- Fc receptors on phagocytic cells facilitate the recognition of antibody-coated targets, leading to destruction via ADCC.
Transcytosis and Passive Immunization
- Transcytosis is the process by which antibodies cross epithelial layers; secretory IgA is a primary species involved.
- Passive immunization occurs when maternal antibodies, particularly IgG, are transmitted to offspring, providing early immunity.
Antibody Diversity and Recognition
- Antibodies exhibit variability, classified into idiotypic and allotypic determinants; idiotypes vary within an individual whereas allotypes vary among individuals of the same species.
- Hybridoma technology enables the production of monoclonal antibodies, combining the specificity of antibodies with the proliferation ability of myeloma cells.
Immune System Related Terms and Structures
- The terms "B-cell receptor (BCR)" and "immunoglobulin superfamily" refer to components integral to the adaptive immune response.
- Class I MHC molecules are associated with the recognition of foreign antigens by T cells.
Key Points on Immune Function
- The signal-transduction pathway initiated by the engagement of antibodies on cell surfaces leads to various immune responses, including phagocytosis.
- The different classes of immunoglobulins are crucial in providing a tailored immune response to diverse pathogens, ensuring overall immune defense.
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Description
Test your knowledge about the diversity and specificity of antibodies, including their production by B cells and the binding to antigenic determinants. Learn about the complex immune response and the generation of monoclonal antibodies.
