Adaptive Immunity - B Cells Quiz

A stepwise process happening mainly in the bone marrow, leading to the creation of mature B cells with unique antigen receptors.

An antigen receptor on the surface of B cells, allowing them to recognize specific antigens.

A process that randomly combines genes to generate diverse BCRs with unique specificities.

A B cell with a membrane-bound IgM antigen receptor (BCR).

A B cell expressing both IgM receptor and IgD receptor.

Process in B cell development where developing B cells expressing a complete BCR are selected.

The enormous number of possible BCR combinations achievable through VDJ recombination.

Essential steps during the process to determine if the constructed B cell is complete and functional.

Immature B cells that strongly bind to self-antigens are removed, preventing autoimmunity.

Turning a naive B cell into an active antibody-producing B cell.

Antigen binding to the B cell receptor (BCR).

Help from a T helper cell.

Protein on the surface of a B cell that recognizes a specific antigen.

Molecule that presents antigens to T helper cells.

A type of T lymphocyte that helps B cells become fully activated and produce antibodies.

A protein on the surface of activated T cells, which binds to the CD40 receptor on B cells.

Signaling molecules that drive B cell proliferation and differentiation.

They are a type of white blood cell that plays a key role in the immune system.

The portion of an antibody that recognizes and binds specifically to a specific antigen.

The ability of an antigen binding site to differentiate between very similar epitopes (parts of an antigen).

The site on an antibody where the C1q protein binds, initiating a chain reaction (complement cascade) to trigger an immune response.

A rapid and efficient mechanism for destroying pathogens, attracting immune cells, and enhancing antibody-mediated immunity.

The antigen-binding site recognizes and binds to specific antigens, while the complement-binding site initiates the complement cascade.

A protein secreted by B cells that binds to specific epitopes on pathogens, triggering immune responses.

The specific part of a pathogen that an antibody recognizes and binds to.

The part of an antibody that varies between different antibodies, responsible for specific antigen recognition.

The part of an antibody that is the same for all antibodies of the same isotype, responsible for activating effector functions.

A class of antibody defined by its constant region, determining which effector functions it activates.

The part of an antibody responsible for binding to the antigen, containing the variable region.

Proteins in the immune system that can be activated by antibodies, leading to the destruction of pathogens.

The fragment, crystallizable portion of an antibody molecule responsible for binding to immune cells and activating effector functions.

The process where a B cell changes the type of antibody it produces, while maintaining the same antigen specificity.

The interaction between CD40 on B cells and CD40L on activated T cells, alongside cytokines released by T helper cells.

The process where B cells produce antibodies with increasing affinity for a specific antigen upon repeated exposure.

Random mutations in the antibody genes produce B cells with varying affinities, and only the highest affinity clones survive due to limited antibody supply.

The various ways antibodies protect the body, beyond simply binding antigens.

Neutralization, opsonization, complement activation, antibody-dependent cell-mediated cytotoxicity (ADCC), and more.

Antibodies block an antigen from binding to its target, preventing infection or damage.

Antibodies coat an antigen, making it easier for phagocytic cells to engulf and destroy it.

Antibodies activate the complement system, leading to the lysis of pathogens and inflammation.

IgG is the most prevalent immunoglobulin in human serum, crucial for various immune functions.

IgG antibodies contribute to opsonization (marking pathogens for destruction), antibody-dependent cell-mediated cytotoxicity (ADCC), neutralization of pathogens, and complement activation.

Neutralization is the process by which antibodies bind to and block the activity of pathogens, preventing them from entering and infecting cells.

The Fab (antigen-binding fragment) region of an antibody is responsible for recognizing and binding to specific antigens, enabling neutralization.

CVID is a condition characterized by low levels of IgG, IgM, and IgA, leading to increased susceptibility to infections.

The most frequent immunodeficiency where B cells cannot produce IgA, usually asymptomatic due to IgM compensation.

A genetic defect affecting B cell development, leading to a complete absence of B cells.

XLA results in recurrent bacterial infections due to a lack of antibodies (immunoglobulins) to fight them.

A process that randomly combines gene segments (V, D, and J) during B cell development to create unique B cell receptors (BCRs) with diverse antigen specificities.

VDJ recombination can generate over 10^11 (100 billion) different BCR combinations.

The B cell receptor (BCR) is a protein on the surface of B cells that recognizes and binds to specific antigens.

B cell development starts with immature B cells in the bone marrow, transitioning to mature B cells in the spleen, with IgM+IgD+ receptors.

Developing B cells are positively selected if they express a complete and functional BCR, ensuring they can recognize antigens.

B cells that fail to express a complete and functional BCR are eliminated, preventing the immune system from reacting to non-specific molecules.

Mature B cells circulate in the spleen, lymph nodes, and blood, waiting to encounter their specific antigen.

Checkpoints are quality control steps during B cell development to ensure that only functional and specific B cells survive and mature.

The specific part of an antigen (like a pathogen) that is recognized by antibodies and T cell receptors.

The variable region of an antibody binds to specific epitopes on antigens, allowing the antibody to target and neutralize specific pathogens.

The constant region of an antibody activates different effector functions like complement proteins or innate immune cells to eliminate the pathogen.

An isotype is a class of antibody defined by its constant region, determining which effector functions it activates.

Fab fragments are the antigen-binding portions of an antibody. They contain the variable regions responsible for recognizing specific epitopes.

Effector functions are the various ways antibodies protect the body beyond simply binding to antigens. These include neutralization, opsonization, complement activation, and ADCC.

Neutralization is when an antibody blocks an antigen from binding to its target, preventing infection or damage to the body.

Opsonization is when antibodies coat an antigen, making it easier for phagocytic cells (like macrophages) to engulf and destroy it.

A protein on activated T helper cells. It binds to CD40 on B cells, providing a co-stimulatory signal for B cell activation.

Signaling molecules produced by T helper cells that drive B cell proliferation and differentiation. They determine the type of antibody the B cell will produce.

The B cell gets fully activated and starts to proliferate and differentiate, creating plasma cells that produce antibodies. It can also become a memory B cell which provides quicker immune response during a future infection.

This interaction ensures that immune responses are specific to the invading pathogen, preventing autoimmune reactions, and leads to fully activated and differentiated B cells capable of producing high affinity antibodies.

Unlike many other lymphocytes, B cells can directly present antigens to T cells, facilitating the activation of T helper cells specifically for that antigen. This enhances the targeted immune response.

Naive B cells haven't encountered their specific antigen yet and remain in a resting state. While activated B cells are actively dividing and differentiating into plasma cells and memory B cells to fight off the infection.

A site on an antibody where the C1q protein binds, initiating the classical complement cascade to destroy pathogens.

A chain reaction initiated by C1q binding to the complement binding site, leading to pathogen destruction and enhanced immune response.

Antibodies on target cells attract immune cells to kill the target cells.

The most abundant antibody at mucosal surfaces, blocking pathogen entry.

The most abundant antibody in the body; able to cross the placenta; involved in all antibody functions.

The first antibody to be produced during an immune response; involved in complement activation.

Attaches to mast cells and eosinophils, implicated in worm infection responses.

Part of the antigen receptor on naïve B cells; its exact role is still being studied.

Antibodies bind to the pathogen's binding site, preventing it from attaching to and entering cells.

IgG binds to the surface of a pathogen, making it easier for phagocytes to recognize and engulf them for destruction.

Antibodies bind to the pathogen's surface and expose a complement binding site, triggering the complement cascade that leads to pathogen lysis.

Antibodies bind to target cells, attracting NK cells and other cytotoxic cells to kill the target cells.

Different antibody classes have different functions, such as IgG for widespread immunity, IgA for mucosal protection, and IgE for fighting parasites.

IgG is the most prevalent antibody in serum, playing a key role in various immune functions.

The process of transforming immature B cells in the bone marrow into mature B cells capable of specific antigen recognition. This involves multiple stages and checkpoints to ensure proper B cell function.

During B cell development, this process ensures that only B cells expressing complete and functional BCRs survive, guaranteeing their ability to recognize antigens effectively.

Two signals are required to fully activate a B cell: 1) antigen binding to the BCR, and 2) help from a T helper cell.

B cells mature primarily in the bone marrow, a spongy tissue inside bones where they develop their unique antigen receptors.

B cells are unique lymphocytes that can directly recognize and bind antigens, making them key players in adaptive immunity.

B cell activation requires two signals: 1) binding of antigen to their BCR (B cell receptor) and 2) help from a T helper cell.

Activated B cells proliferate and differentiate into plasma cells, which produce antibodies, and memory B cells, which provide a quicker immune response upon future encounters with the same antigen.

CD40L, expressed on activated T helper cells, interacts with CD40 on the surface of B cells, providing a crucial co-stimulatory signal for B cell activation.

A chain reaction triggered by C1q binding to the complement binding site on an antibody, ultimately destroying pathogens and enhancing immune response.

The antigen-binding site recognizes and binds to specific antigens, while the complement-binding site activates a chain reaction (complement cascade) to eliminate pathogens.

Essential quality control steps during B cell development that ensure only functional and specific B cells survive and mature. These checkpoints prevent the production of harmful B cells.

Both are types of B cell receptors. IgM is expressed first by immature B cells, while IgD is expressed later by mature B cells. They differ in their roles and functions in the immune response.

B cells play a crucial role in adaptive immunity by producing antibodies that target and destroy pathogens. They also act as antigen-presenting cells (APCs), helping to activate T cells.

Antibodies can neutralize pathogens, opsonize them for destruction, activate complement, and mediate antibody-dependent cell-mediated cytotoxicity (ADCC).

A chain reaction triggered by C1q binding to a complement binding site on an antibody, ultimately destroying pathogens and enhancing immune response.

A specialized protein on the surface of certain immune cells that binds to the Fc (fragment, crystallizable) portion of antibodies. This binding allows immune cells like macrophages and NK cells to engage and destroy pathogens.

A crucial interaction between CD40 on B cells and CD40L on activated T helper cells. This interaction provides a co-stimulatory signal needed for B cell activation.