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What is the function of the immune system in the body?
What is the function of the immune system in the body?
The immune system defends the body against pathogens that enter the body.
What are the two types of barriers in the first line of defense?
What are the two types of barriers in the first line of defense?
Which of the following are examples of physical barriers in the first line of defense?
Which of the following are examples of physical barriers in the first line of defense?
What is the function of the second line of defense?
What is the function of the second line of defense?
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What are the two types of lymphocytes involved in the acquired immune response?
What are the two types of lymphocytes involved in the acquired immune response?
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T-lymphocytes mature in the bone marrow.
T-lymphocytes mature in the bone marrow.
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What do B-lymphocytes produce after they mature?
What do B-lymphocytes produce after they mature?
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What are immunoglobulins?
What are immunoglobulins?
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What is the function of antibodies in the immune response?
What is the function of antibodies in the immune response?
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What is the name for large antigens that elicit an immune response?
What is the name for large antigens that elicit an immune response?
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What is the name for small foreign molecules that cannot elicit an immune response alone?
What is the name for small foreign molecules that cannot elicit an immune response alone?
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What are protein markers on the surface of cells that determine the antigen called?
What are protein markers on the surface of cells that determine the antigen called?
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What types of domains are present in both light and heavy chains of immunoglobulins?
What types of domains are present in both light and heavy chains of immunoglobulins?
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Which region of the antibody is responsible for binding to the antigen?
Which region of the antibody is responsible for binding to the antigen?
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The constant region of the heavy chain can vary depending on the antibody class.
The constant region of the heavy chain can vary depending on the antibody class.
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What types of bonds link the light and heavy chains in an immunoglobulin molecule?
What types of bonds link the light and heavy chains in an immunoglobulin molecule?
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Which of the following statements is true about the structure of immunoglobulins?
Which of the following statements is true about the structure of immunoglobulins?
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What is the structural motif of all Ig domains?
What is the structural motif of all Ig domains?
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The “one gene, one protein” concept is valid for the immune system.
The “one gene, one protein” concept is valid for the immune system.
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How many genes are involved in the production of the light chain of an antibody?
How many genes are involved in the production of the light chain of an antibody?
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What regions are responsible for the amazing specificity of antibodies?
What regions are responsible for the amazing specificity of antibodies?
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What are the two main types of interactions between an antigen and an antibody?
What are the two main types of interactions between an antigen and an antibody?
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Small antigens called haptens can elicit an immune response on their own.
Small antigens called haptens can elicit an immune response on their own.
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What is the main factor that determines the class of an immunoglobulin?
What is the main factor that determines the class of an immunoglobulin?
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Which class of immunoglobulin is the only one that can cross the placenta?
Which class of immunoglobulin is the only one that can cross the placenta?
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Which immunoglobulin class is involved in the immediate hypersensitivity reactions?
Which immunoglobulin class is involved in the immediate hypersensitivity reactions?
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What is the function of the hinge region in IgD, IgA, and IgG?
What is the function of the hinge region in IgD, IgA, and IgG?
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IgE and IgM have an additional constant region instead of a hinge region.
IgE and IgM have an additional constant region instead of a hinge region.
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What is the main difference in the structure of IgM compared to IgG?
What is the main difference in the structure of IgM compared to IgG?
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Antibodies are a type of cell.
Antibodies are a type of cell.
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T-lymphocytes have a role in cell-mediated immunity, and B-lymphocytes are involved in humoral immunity.
T-lymphocytes have a role in cell-mediated immunity, and B-lymphocytes are involved in humoral immunity.
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What is the main function of the Fc region of an antibody?
What is the main function of the Fc region of an antibody?
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Which of the following enzymes cut the antibody molecule at the hinge region, producing two Fab fragments and one Fc fragment?
Which of the following enzymes cut the antibody molecule at the hinge region, producing two Fab fragments and one Fc fragment?
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Which enzyme cuts the antibody under the hinge region, yielding one Fab fragment and one Fc fragment?
Which enzyme cuts the antibody under the hinge region, yielding one Fab fragment and one Fc fragment?
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What is the role of complement proteins in the immune response?
What is the role of complement proteins in the immune response?
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The Fc region of an antibody can directly activate intracellular signaling pathways.
The Fc region of an antibody can directly activate intracellular signaling pathways.
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The antigen-binding site of an antibody is highly variable.
The antigen-binding site of an antibody is highly variable.
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What is the main way the immune system generates a diverse array of antibodies?
What is the main way the immune system generates a diverse array of antibodies?
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Which of the following is NOT a factor in the diversity of antibodies?
Which of the following is NOT a factor in the diversity of antibodies?
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The immune system can produce antibodies against any possible antigen.
The immune system can produce antibodies against any possible antigen.
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What is the term used to describe the phenomenon where a large antigen elicits an immune response, activating all or most of the CDRs on an antibody?
What is the term used to describe the phenomenon where a large antigen elicits an immune response, activating all or most of the CDRs on an antibody?
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The complement system is activated only by antibodies.
The complement system is activated only by antibodies.
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The immune response to a small antigen (hapten) is typically weaker than the response to a large antigen.
The immune response to a small antigen (hapten) is typically weaker than the response to a large antigen.
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Study Notes
Biochemistry: Immunoglobulins (Antibodies)
- The immune system defends the body against pathogens through defense mechanisms.
- Non-specific (Innate) immunity forms the first line of defense:
- Physical barriers: skin, hair, mucous membranes.
- Chemical barriers: sweat, tears, saliva, stomach acid, urine.
- Non-specific (Innate) immunity forms the second line of defense:
- If pathogens pass the first line, phagocytic white blood cells and antimicrobial proteins trigger an inflammatory response.
- Specific (Acquired) immunity is the third line of defense:
- Lymphocytes and antibodies are acquired to combat pathogens.
- Two types of lymphocytes:
- T-lymphocytes: involved in cell-mediated immunity (graft rejection, hypersensitivity, defense against malignant cells and viruses).
- B-lymphocytes: mature into plasma cells, producing antibodies that create humoral immunity. Plasma cells secrete immunoglobulins in response to exposure to antigens.
- Immunoglobulins (Antibodies):
- Glycoproteins with four polypeptide chains (two light and two heavy), bonded by disulfide bonds (quaternary structure).
- Bind to foreign molecules (antigens), even novel ones, acting as a defense mechanism.
- The Y-shaped antibodies bind to two identical antigens at their tips.
- Effects of antibody binding to antigens include prevention of binding to other molecules or blocking toxin-induced effects.
- Antigens:
- Foreign molecules that antibodies bind to.
- Larger antigens (immunogens) trigger antibody production; smaller ones (haptens) cannot.
- Cell Recognition as Foreign:
- Proteins on cell surfaces (epitopes) signal foreign identity to the immune system.
- Immunoglobulin Structure:
- Composed of light chains (25kDa) and heavy chains (50kDa).
- Linked by inter and intra-chain disulfide bonds, forming a ~150kDa antibody.
- Divided into Fab (antigen-binding) and Fc (crystallizable) fragments, cut by enzymes like papain and pepsin, influencing antigen interactions.
- Antibody binding is highly specific to the antibody and the antigen with multiple interactions( electrostatic, hydrogen bonds).
- The high variability is crucial for immunity.
- Immune Diversity:
- The immune system generates a vast library of antibodies (~10^8) through gene rearrangements.
-Gene involved and antibody variability:
- Variable (VH), Diversity(D), Joining (J), Constant (CH) regions that in combination allow for a wide array of antibodies.
- The immune system generates a vast library of antibodies (~10^8) through gene rearrangements.
-Gene involved and antibody variability:
- Frameworks regions and variability among proteins:
- Determine how much amino acids change.
- Constant Region:
- Constant region gene is the C1 kappa or lamba
- Hypervariable regions (CDRs):
- Portions of the antibody that precisely recognize specific epitopes on antigens. Located on loops of variable domains.
Immunoglobulin Classes Overview
- IgG, IgE, IgD, IgM, IgA
- Specific characteristics (heavy chains) and functions (placental crossing, complement fixation).
- IgG is highly prevalent and found in the bloodstream.
- IgM is involved in the initial immune response.
- IgA is found in secretions.
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Description
Explore the role of immunoglobulins, or antibodies, in the immune system's defense against pathogens. This quiz covers the distinctions between non-specific and specific immunity, including the functions of T-lymphocytes and B-lymphocytes. Test your understanding of innate and acquired immunity mechanisms.
