Immunology: Antibody Production & T Cells

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Questions and Answers

What is the main function of plasma cells in the primary immune response?

To destroy pathogens

To produce antibodies (correct)

To activate T cells

To form memory cells

How long does it typically take for plasma cells to become effective against an antigen during the primary response?

1-3 days

1-2 weeks

3-14 days (correct)

2-4 weeks

Which type of T cell is primarily responsible for activating B cells?

Regulatory T cells

Cytotoxic T cells

Memory T cells

Helper T cells (correct)

What occurs during the secondary immune response?

B memory cells rapidly divide to form plasma cells Signup and view all the answers

What is the function of regulatory T cells in the immune response?

To turn off the immune system response Signup and view all the answers

Which type of immunity arises from the transfer of antibodies from mother to child?

Naturally acquired passive immunity Signup and view all the answers

Which of the following antigens can cell-mediated immunity effectively target?

Bacteria, viruses, fungi, and protozoa Signup and view all the answers

Which state best describes naturally acquired active immunity?

Immunity that develops after infection with an antigen Signup and view all the answers

Which type of lymphocyte is primarily responsible for antibody-mediated immunity?

B cells Signup and view all the answers

What type of immunity is characterized by specific recognition of antigens and has memory?

Adaptive immunity Signup and view all the answers

Where do B cells mature before moving to lymphatic tissue?

Red bone marrow Signup and view all the answers

What is the role of stem cells in relation to lymphocytes?

They give rise to all blood cells, including lymphocytes. Signup and view all the answers

What characteristic distinguishes adaptive immunity from innate immunity?

Presence of memory Signup and view all the answers

What stimulates the release of chemical mediators in response to injury?

The presence of foreign substances Signup and view all the answers

Which of the following substances can act as an antigen?

Bacteria, pollen, and food Signup and view all the answers

Which statement is true about the development of lymphocytes?

They differentiate from stem cells in red bone marrow. Signup and view all the answers

What is the primary function of the skin and mucous membranes in the immune system?

To act as barriers against pathogens Signup and view all the answers

Which of the following is a chemical mediator that helps protect against bacterial infections?

Lysozyme Signup and view all the answers

What is the role of phagocytic cells in the immune response?

To ingest and destroy foreign substances Signup and view all the answers

Which type of white blood cell is typically the first to respond to an infection?

Neutrophils Signup and view all the answers

What is the primary function of basophils in the immune system?

To release histamine and promote inflammation Signup and view all the answers

What do interferons stimulate surrounding cells to produce?

Antiviral proteins Signup and view all the answers

Where are macrophages primarily derived from?

Monocytes Signup and view all the answers

What is the function of natural killer cells in the immune response?

To recognize and destroy tumor and virus-infected cells Signup and view all the answers

What is the primary role of T cells in the immune response?

Involved in cell-mediated immunity Signup and view all the answers

Where do T cells mature in the human body?

Thymus gland Signup and view all the answers

What is the function of antigen receptors on lymphocytes?

Bind with a specific antigen Signup and view all the answers

What do major histocompatibility complex (MHC) molecules do?

Present processed antigens on cell surfaces Signup and view all the answers

What do helper T cells secrete to stimulate B cell production?

Interleukin-2 Signup and view all the answers

What is the role of interleukin-1 in the immune response?

Stimulate helper T cells Signup and view all the answers

Which type of immunity is primarily mediated by B cells?

Adaptive immunity Signup and view all the answers

What is the function of cytokines in the immune system?

Regulate neighbor cells Signup and view all the answers

What type of immune response is primarily involved in combating antigens present in body fluids such as blood and lymph?

Antibody-mediated immunity Signup and view all the answers

Which component of the antibody structure is responsible for binding to specific epitopes of an antigen?

Variable region Signup and view all the answers

How many different immunoglobulins are identified as effective in destroying antigens?

5 Signup and view all the answers

What is the primary function of antibodies in the immune response?

Inactivate antigens Signup and view all the answers

Which part of the antibody structure can vary among different classes of immunoglobulins?

Constant region Signup and view all the answers

What is the term used to describe the number of antigen-binding sites on an antibody?

Valence Signup and view all the answers

Which of the following effects is NOT attributable to antibodies?

Repair damaged tissues Signup and view all the answers

Which type of immune response utilizes B cells to produce antibodies?

Humoral response Signup and view all the answers

Study Notes

### Antibody Production

The primary response occurs when a B cell is first exposed to an antigen.
The B cell undergoes division and forms plasma cells and memory cells.
- Plasma cells produce antibodies.
- Plasma cells can take 3-14 days to become effective against an antigen. It is during this time that a person experiences disease symptoms.
- Memory cells are quickly produced during the second exposure to an antigen.
- These cells quickly divide and create plasma cells that produce antibodies.
- The process also produces more memory cells.

Cell-Mediated Immunity

Cell-mediated immunity is effective against antigens in cells and tissues.
Cell-mediated immunity is effective against bacteria, viruses, fungi, and protozoa.
This type of immunity uses different types of T cells.

Types of T Cells

Helper T cells (TH)
- Activate macrophages
- Help form B cells
- Promote the production of Tc cells
Cytotoxic T cells (Tc)
- Precursor to cytotoxic T lymphocytes (CTL)
Cytotoxic T lymphocytes (CTL)
- Destroy antigens on contact
Regulatory T cells (Tr)
- Turn off the immune system response when an antigen is gone

Types of Adaptive Immunity

Naturally Acquired Immunity
- Active
  - Natural exposure to antigens causes the production of antibodies.
  - Can lead to lifelong immunity.
  - Example: Mononucleosis.
- Passive
  - The transfer of antibodies from mother to child.
  - Example: Breast milk or placenta.

Innate Immunity

Present at birth.
Defends the body against any pathogen.
Accomplished by physical barriers, chemical mediators, cells, and inflammatory response.

Physical Barriers

First line of defense.
Skin and mucous membranes act as barriers.
Tears, saliva, and urine wash away pathogens.

Chemical Mediators

Chemicals that can kill microbes and prevent them from entering cells.
Lysozyme
- Found in tears and saliva
- Kills bacteria
Mucous Membranes
- Prevent entry of microbes
Histamine
- Promotes inflammation by causing vasodilation.
Interferons
- Proteins that protect against viral infections by stimulating surrounding cells to produce antiviral proteins.

Cells

White Blood Cells
- Produced in red bone marrow and lymphatic tissue to fight foreign substances.
Phagocytic Cells
- Ingest and destroy foreign substances.
- Examples: Neutrophils and macrophages
- Neutrophils
  - First to respond to infection but die quickly
- Macrophages
  - Monocytes that leave the blood and enter tissues
  - Can ingest more material than neutrophils.
  - Protect lymph in lymph nodes and blood in the spleen and liver.
  - Given specific names for certain areas of the body (Kupffer cells in the liver).
Basophils
- Made in red bone marrow.
- Leave the blood and enter infected tissues.
- Can release histamine.
Mast Cells
- Made in red bone marrow.
- Found in the skin, lungs, gastrointestinal tract, urogenital tract.
- Can release leukotrienes.
Eosinophils
- Produced in red bone marrow.
- Release chemicals to reduce inflammation.
Natural Killer Cells
- Type of lymphocyte.
- Produced in red bone marrow.
- Recognize classes of cells, such as tumor cells or virus-infected cells.
- Release chemicals to lyse cells.

Inflammatory Response

A chemical and cellular response to injury.
Triggered by the presence of foreign substances.
Stimulates the release of chemical mediators.

Adaptive Immunity

Defenses that involve specific recognition of a particular antigen.
Acquired after birth.
Initiates when innate defenses fail.
Slower than innate immunity but has memory.
Employs lymphocytes (B and T cells).
Two types: Antibody-mediated and cell-mediated.

Antigen
- A substance that stimulates an immune response. Example: Bacteria, virus, pollen, food, drugs, etc.
Self-antigen
- A molecule produced by a person's body that stimulates an immune system response.
Antibody
- Proteins the body produces in response to an antigen.

Origin and Development of Lymphocytes

Stem Cells
- Found in red bone marrow.
- Give rise to all blood cells.
- Give rise to some pre-T cells and pre-B cells.
Lymphocytes
- Type of white blood cell.
- Involved in adaptive immunity.
- Develop from stem cells.
- Differentiate into specific lymphocytes, such as B and T cells.
B cells
- Type of lymphocyte.
- Involved in antibody-mediated immunity.
- Originate from stem cells.
- Mature in red bone marrow.
- Move to lymphatic tissue after maturation.
- Lead to antibody production.
T cells
- Type of lymphocyte.
- Involved in cell-mediated immunity primarily and antibody-mediated immunity.
- Mature in the thymus gland.
- Move to lymphatic tissue after maturation.
- Four types of T cells.

Antigen Recognition

Lymphocytes have antigen receptors on their surface.
- Called B-cell receptors on B cells and T-cell receptors on T cells.
- Each receptor only binds with a specific antigen.
When antigen receptors combine with an antigen, the lymphocyte is activated, and adaptive immunity begins.

Major Histocompatibility Complex Molecule (MHC)

Contain binding sites for antigens.
Specific for certain antigens.
Hold and present a processed antigen on the surface of the cell membrane.
Bind to antigen receptors on B or T cells and stimulate a response.

Cytokines

Proteins secreted by a cell that regulate neighboring cells.
Example: Interleukin 1 released by macrophages stimulates helper T cells.

Lymphocyte Proliferation

After an antigen is processed and presented to helper T cells, the helper T cell produces interleukin-2 and interleukin-2 receptors.
Interleukin-2 binds to receptors and stimulates the production of more helper T cells.
Helper T cells are needed to produce B cells.
B cells produce antibodies.

Dual Nature of the Immune System

Lymphocytes give rise to two types of immune responses: antibody-mediated and cell-mediated.
Antigens can trigger both types of responses.
Both types can recognize self vs. non-self, use specificity, and have memory.

Antibody-Mediated

Effective against antigens in body fluids (blood and lymph).
Effective against bacteria, viruses, and toxins.
Employs B cells to produce antibodies.

Antibody Structure

Letter "Y" shape.
- Variable region: The "V" of the "Y". Binds to epitopes of an antigen using an antigen-binding site.
- Constant region: The stem of the "Y". Each class of immunoglobulin has the same structure.
Antigen-binding site: Site on an antibody where an antigen binds.
Valence: Number of antigen-binding sites on an antibody.
Five immunoglobulins used to destroy antigens: IgG, IgM, IgA, IgE, IgD

Effects of Antibodies

Inactivate antigens
Bind antigens together
Activate complement cascades
Initiate the release of inflammatory chemicals
Facilitate phagocytosis

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Description

This quiz focuses on the mechanisms of antibody production and cell-mediated immunity. Learn how B cells and T cells interact with antigens and the types of responses they generate during immune reactions. Test your knowledge of plasma cells, memory cells, and the different types of T cells involved in immune defense.