Immunology Chapter 15 Flashcards

Questions and Answers

Match each of the antibody classes with its description.

IgM = First class produced in primary response. Forms a pentamer. Helps activate complement through the classical pathway. IgG = Main class found in blood. Only class that can cross the placenta. Found as a monomer. IgA = Most abundant class overall, but mainly found in mucosal secretions. Generally found as a dimer. IgE = Binds via Fc region to mast cells/basophils. Involved in allergic responses and responses to parasites. IgD = Involved in maturation of B lymphocytes and antibody responses, but function is largely uncharacterized.

Select all of the following that apply to a secondary response to a T-dependent antigen:

May take only 2-4 days to build a substantial amount of antibodies in the bloodstream. (correct)

Fine-tunes and increases strength of binding of antibody to antigen through the process of affinity maturation. (correct)

Produces mainly either IgG or IgA antibodies without shifting to other types. (correct)

Cytotoxic T cells primarily are responsible for?

cell-mediated immunity.

Match the statements to the terms they describe regarding the possible end results of antibody binding to antigen.

Opsonization = Coating of microbe with antibody to enhance phagocytosis Neutralization = Antibodies fill the surface receptors on microbe to prevent attachment to the host Complement system activation = Immune complexes activate complement proteins, leading to inflammation and production of MACs Immobilization and prevention of adherence = Antibodies bind to flagella preventing movement or to pili preventing attachment of bacteria Cross-linking = Formation of large Ab-Ag complexes as a result of the Ab binding two separate antigens Antibody-dependent cellular cytotoxicity (ADCC) = IgG molecules attach to a cell targeting it for attack by a NK cell Signup and view all the answers

Please place the lymphocytes in the correct order in terms of clonal selection and expansion.

1 - Immature lymphocytes, 2 - Naive lymphocytes, 3 - Activated lymphocytes, 4 - Effector lymphocytes, 5 - Memory lymphocytes Signup and view all the answers

You are infected with an enveloped single-stranded RNA virus. Your immune system recognizes the antigen and responds. Plasma cells generate antibodies that bind to the virus, preventing it from entering your cells. This is an example of?

neutralization. Signup and view all the answers

IgM is particularly effective in cross-linking antigens because?

it is a pentamer. Signup and view all the answers

Select the INCORRECT statement regarding the outcomes of antigen-antibody binding.

False Signup and view all the answers

If your cell-mediated immune response were compromised, which of the following would happen?

You would be more susceptible to viral infections. Signup and view all the answers

A term synonymous with antibody is?

immunoglobulin. Signup and view all the answers

Which part accounts for antigen-binding specificity?

A Signup and view all the answers

If your humoral immune response were compromised, which of the following would happen?

Antibody production would decrease. Signup and view all the answers

The adaptive immune response?

involves memory of antigens from previous exposure. Signup and view all the answers

T cells?

are responsible for cell-mediated immunity. Signup and view all the answers

Antigens?

are molecules that can be recognized by B or T cells. Signup and view all the answers

After repeated exposure to foreign material, innate immunity continues to react the same way.

True Signup and view all the answers

______ with antigen fragments displayed on their surfaces are known as antigen-presenting cells (APCs).

Macrophages Signup and view all the answers

When activated by antigen-presenting cells, helper T cells release what cytokine that activates B cells and cytotoxic T cells?

Interleukin-2 Signup and view all the answers

Cytotoxic T cells know that a cell is infected because?

that cell has antigens from the disease-causing microbe on its surface. Signup and view all the answers

B cells differentiate into ______, which make antibodies.

plasma cells Signup and view all the answers

The immune system responds more quickly to second exposure to an antigen because?

memory B cells are produced during the first response. Signup and view all the answers

Select all of the statements that apply to a primary response to a T-dependent antigen:

Takes 10-14 days to build a substantial amount of antibodies in the bloodstream. Signup and view all the answers

Please match the antibody type to the statement that accurately describes them.

IgG = Most prevalent antibody in circulation IgA = Dimer that is a significant component of mucus and secretions IgM = Pentameric in circulation IgD = Involved in the development/maturation of immune response IgE = Mediates allergic responses Signup and view all the answers

Antibodies are made by?

B cells/plasma cells. Signup and view all the answers

Which of the following is the only antibody class capable of crossing the placenta?

IgG Signup and view all the answers

The antibody-producing progeny of an activated B cell are called ______.

plasma cells Signup and view all the answers

There are no antigens that can stimulate B cells without T cell help.

False Signup and view all the answers

T-dependent antigens?

characteristically have a protein component. Signup and view all the answers

Antigen-presenting cells?

All of the answer choices are correct. Signup and view all the answers

All of the following cells have class II MHC receptors on their surface EXCEPT:

Red blood cells Signup and view all the answers

Helper T cells?

function in both cell-mediated and humoral immunity. Signup and view all the answers

Study Notes

Antibody Classes

IgM: First antibody produced in primary immune response. Forms a pentamer. Activates complement through classical pathway.
IgG: Main antibody found in blood. Only class capable of crossing the placenta. Exists as a monomer.
IgA: Most abundant antibody class, particularly in mucosal secretions. Typically found as a dimer.
IgE: Binds to mast cells and basophils. Plays a key role in allergic reactions and defense against parasites.
IgD: Involved in the maturation of B lymphocytes, but its function remains largely uncharacterized.

Secondary Immune Response

Rapid antibody production (2-4 days) upon re-exposure to an antigen.
Primarily produces IgG or IgA without switching to other antibody types.
Enhances binding strength of antibodies via affinity maturation.

Cytotoxic T Cells

Responsible for mediating cell-mediated immunity, targeting infected or cancerous cells.

Antibody Function Outcomes

Opsonization: Coating microbes with antibodies to enhance phagocytosis.
Neutralization: Antibodies block surface receptors on pathogens, preventing host cell entry.
Complement Activation: Immune complexes activate complement proteins, initiating inflammation and forming Membrane Attack Complexes (MACs).
Immobilization: Antibodies prevent bacterial movement and attachment by binding to flagella or pili.
Cross-linking: Formation of large aggregates of antibody-antigen complexes.
Antibody-dependent Cellular Cytotoxicity (ADCC): IgG marks target cells for destruction by Natural Killer (NK) cells.

Lymphocyte Development

Immature Lymphocytes: Antigen receptors are not fully developed.
Naive Lymphocytes: Have antigen receptors but haven't encountered an antigen.
Activated Lymphocytes: Antigen binding and receiving proliferation signals.
Effector Lymphocytes: Produce cytokines in response to specific antigens.
Memory Lymphocytes: Long-lived cells that quickly respond to previously encountered antigens.

Neutralization Example

Antibodies generated by plasma cells neutralize enveloped viruses, blocking their entry into cells.

Importance of IgM

IgM is especially effective for cross-linking due to its pentameric structure.

Vulnerabilities of Immune Response

Compromised cell-mediated immunity increases susceptibility to viral infections.
Compromised humoral immunity results in decreased antibody production.

Adaptive Immune Response

Adaptive immunity enables memory for previously encountered antigens, enhancing response speed upon re-exposure.

Antigen-presenting Cells (APCs)

Macrophages present antigen fragments for recognition by T cells.

Helper T Cells

Activated by APCs, they release interleukin-2 to stimulate B cells and cytotoxic T cells.

Antigen Recognition

Cytotoxic T cells identify infected cells via surface antigens from pathogens.

B Cell Function

B cells differentiate into plasma cells, which are responsible for antibody production.

Memory B Cells

Provide rapid response during subsequent exposures to the same antigen.

Primary Immune Response

Takes 10-14 days for antibody levels to rise significantly.
Initially produces IgM but eventually shifts to other classes through class switching.

Antibody Types and Functions

IgG: Most prevalent in circulation.
IgA: Key component of mucus and secretions.
IgM: Exists as a pentamer in circulation.
IgD: Participates in immune response development.
IgE: Involved in allergic reactions.

Plasma Cells

Antibodies are produced by B cells that have differentiated into plasma cells.

Antigen-stimulated B Cell Activation

Incorrect belief that no antigens can stimulate B cells without T cell help; this statement is false.

Characteristics of T-dependent Antigens

Typically contains protein components that require T cell assistance for B cell activation.

Class II MHC Receptors

Cells with class II MHC receptors include professional APCs; red blood cells do not express these receptors.

Helper T Cells Role

Integral to both cell-mediated and humoral immune responses, coordinating actions of various immune cells.

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Description

Test your knowledge of different antibody classes with this flashcard quiz. Each card presents a matching question about the characteristics and functions of IgM, IgG, IgA, and IgE antibodies. Perfect for studying immunology concepts and preparing for exams.