The Humoral Response and B Lymphocytes

Questions and Answers

What is the origin of B lymphocytes?

Thymus

Liver

Spleen

Bone marrow (correct)

What is the function of the proteins on the surface of B cells?

They act as receptors for antigens (correct)

They help in cell division

They aid in cell signaling

They provide structural support

What is another name for antibodies?

Cytokines

Antigens

Immunoglobulins (correct)

Immunoproteins

How many proteins are present on the surface of a B cell?

Close to 10,000 Signup and view all the answers

What type of antibodies are present on the surface of B cells?

Membrane-bound antibodies Signup and view all the answers

What is unique about the membrane-bound antibodies on a B cell?

They are all different Signup and view all the answers

What is the term for the organ where B cells originate, leading to the 'B' in B cells?

Bursa of Fabricius Signup and view all the answers

How many separate proteins make up the membrane-bound antibody complex on a B cell?

4 Signup and view all the answers

What is the main difference between the antibodies on the surface of one B cell and another B cell?

Their variable portions are different. Signup and view all the answers

Why do B cells have a lot of shuffling of the portion of their DNA that codes for the variable portions?

To intentionally create diversity in the variable portions. Signup and view all the answers

What is the purpose of having so many different combinations of variable portions on B cells?

To be able to respond to any potential pathogen. Signup and view all the answers

What happens when a B cell binds to a foreign pathogen?

It produces more antibodies with the same variable portion. Signup and view all the answers

What is an epitope?

A part of a foreign protein that an antibody binds to. Signup and view all the answers

Why is it important for the immune system to have B cells with many different combinations of variable portions?

So that it can respond to any potential pathogen. Signup and view all the answers

What happens to the DNA of B cells during their development?

It is intentionally reshuffled. Signup and view all the answers

What is the main advantage of having many different B cells with different variable portions?

It allows the immune system to respond to any potential pathogen. Signup and view all the answers

What is the purpose of the variable portion of an antibody?

To bind to a specific part of a pathogen. Signup and view all the answers

How many different combinations of variable portions are possible?

10^10 Signup and view all the answers

What is one way that antibodies can make it harder for viruses to function?

By forming a complex with multiple viruses Signup and view all the answers

What is the purpose of the variable portion on each antibody?

To bond to the epitope on a virus Signup and view all the answers

What is the result of antibodies binding to multiple viruses?

The viruses are less infectious and can be easily recognized by phagocytes Signup and view all the answers

Why are antibodies effective against a wide range of pathogens?

Because they can recognize a wide range of epitopes Signup and view all the answers

What is the term for the process by which phagocytes recognize and engulf antibody-bound pathogens?

Opsonization Signup and view all the answers

What is a challenge that remains to be solved in the field of immunology?

Eliminating cancer cells that have infiltrated normal tissues Signup and view all the answers

What happens to the B cells that respond to the body's own cells?

They are eliminated or 'weeded out' Signup and view all the answers

What is the primary role of effector cells?

To produce antibodies Signup and view all the answers

What is the function of opsonization?

To mark pathogens for phagocytosis Signup and view all the answers

What happens to the number of B cells with the perfect receptor after the initial response?

It increases Signup and view all the answers

Why do B cells need help from helper T cells to become activated?

Because it's a fail-safe mechanism to prevent autoimmune responses Signup and view all the answers

What is the role of memory cells?

To remain in the body and respond to future infections Signup and view all the answers

How many antibodies can an activated effector cell produce per second?

2,000 Signup and view all the answers

What is the result of the humoral response?

The presence of many antibodies in the body Signup and view all the answers

What is the purpose of the immune system's 'weeding out' process?

To prevent autoimmune responses Signup and view all the answers

What is the difference between the number of possible B cell combinations and the actual number of B cells?

The actual number is smaller Signup and view all the answers

Study Notes

Humoral Response and B Lymphocytes (B Cells)

B cells are a subset of white blood cells called lymphocytes that come from the bone marrow.
Each B cell has approximately 10,000 proteins on its surface, known as membrane-bound antibodies or immunoglobulins.
These membrane-bound antibodies are protein complexes with four separate proteins and have a variable part that can take on many different forms.

Diversity of B Cells and Antibodies

Each B cell has a unique combination of membrane-bound antibodies with the same variable portion.
There are approximately 10 billion different combinations of variable portions possible.
The diversity of B cells arises from intentional reshuffling of the DNA that codes for the variable portions during B cell development.

Role of B Cells in Immune Response

B cells can recognize and bind to specific pathogens, such as viruses and bacteria, through their membrane-bound antibodies.
When a B cell binds to a pathogen, it becomes activated and starts cloning itself, producing multiple versions of itself.
Activated B cells can differentiate into two forms: memory cells and effector cells.
Memory cells stick around for a long time, allowing for a faster response to future infections.
Effector cells, also known as plasma cells, produce large quantities of antibodies that can bind to specific pathogens.

Antibodies and Immune Response

Antibodies are proteins produced by effector cells that can bind to specific pathogens.
Antibodies can tag pathogens for pickup by phagocytes, making it easier for them to be removed from the body (opsonization).
Antibodies can also make it harder for pathogens to function and infiltrate cells.
Each antibody has two identical heavy chains and two identical light chains, with a specific variable portion that can bond to epitopes on pathogens.

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Description

Learn about the humoral response, which involves B lymphocytes, a type of white blood cell. B cells have thousands of proteins on their surface and originate from the bone marrow.