B Lymphocytes and Antibodies Quiz

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What do B cells assemble in the bone marrow?

Soluble forms of IgM and IgD with different antigen binding sites

Cell surface forms of IgM monomer (sIgM) and IgD (sIgD) with the same antigen binding site (correct)

Cell surface forms of IgM monomer (sIgM) and IgD (sIgD) with different antigen binding sites

Soluble forms of IgM and IgD with the same antigen binding site

What are the 3 outcomes of B cells in the bone marrow that express sIgM and sIgD and recognize self-antigens?

Undergo apoptosis, undergo further DNA rearrangement of surface Ig, or migrate to the spleen and lymph nodes (correct)

Undergo apoptosis, undergo further DNA rearrangement of surface Ig, or differentiate into effector B cells

Undergo apoptosis, undergo further DNA rearrangement of surface Ig, or differentiate into plasma cells

Undergo apoptosis, migrate to the spleen and lymph nodes, or differentiate into memory B cells

What are the first 2 antibodies produced in an antibody response?

IgG and IgA

IgD and IgM (correct)

IgA and IgE

IgG and IgM

How are B lymphocytes in the spleen or lymph nodes activated?

Antigens are recognized by B cells on the surface of macrophages or follicular dendritic cells, and T helper cells provide signal 2 via CD154-CD40 interaction and cytokine secretion Signup and view all the answers

What are the 3 outcomes of B cell proliferation?

Class switching, plasma cells, and memory B cells Signup and view all the answers

What is class switching in B cells determined by, and what are the 3 responses?

Th1 cytokines (IL-4, IL-21) leading to IgG1 and IgG3, Th2 cytokines (IL-4) leading to IgE, and IL-21 leading to IgA Signup and view all the answers

What cytokine can block IgA activation?

IL-4 Signup and view all the answers

What occurs simultaneously with class switching, and what enzyme initiates both processes?

Somatic hypermutation, and Activation Induced Cytidine Deaminase (AID) Signup and view all the answers

Why is the secondary antibody response stronger than the primary response?

Due to affinity maturation caused by class switching and somatic hypermutation Signup and view all the answers

What initiates somatic hypermutation in B cells?

Activation Induced Cytidine Deaminase (AID) Signup and view all the answers

Which antibody class is activated by IL-21 cytokine?

IgA Signup and view all the answers

What is the main function of AID in B cells?

Converting cytosine to uracil Signup and view all the answers

Which outcome is a result of competition during somatic hypermutation?

Higher affinity plasma cells Signup and view all the answers

What determines the specificity of IgG1 and IgG3 antibodies produced by B cells?

Th1 response Signup and view all the answers

What is the main role of class switching in B cells?

Producing antibodies of different classes Signup and view all the answers

Which response activates IgE antibodies in B cells?

Th2 response Signup and view all the answers

What is the outcome of Th cell recognition of MHC II on B cells?

Induction of antibody production Signup and view all the answers

How does the affinity maturation process affect B cell responses?

Results in stronger secondary responses Signup and view all the answers

What process introduces point mutations in V region exons during RNA transcription in B cells?

Somatic hypermutation Signup and view all the answers

What is the initial cell type that gives rise to B lymphocytes?

Pluripotent hematopoietic stem cell Signup and view all the answers

What is the sequence of maturation stages for a B cell?

Pluripotent hematopoietic stem cell, common lymphoid progenitor, pro-B cell, mature naive B cell Signup and view all the answers

Which region of an antibody is responsible for binding to antigens?

Fab region Signup and view all the answers

What are the polypeptide components of an antibody?

2 identical heavy chains (Mr 50K) and 2 identical light chains (Mr 25K) Signup and view all the answers

Which domains of an antibody form the binding site for antigens?

Adjacent N-terminal VL and VH domains Signup and view all the answers

What is the primary function of antibodies?

Binding to infectious microorganisms and preventing infection Signup and view all the answers

Which of the following is NOT a mechanism by which antibodies prevent infection?

Neutralizing toxins produced by microorganisms Signup and view all the answers

What is the alternative name for antibodies?

Immunoglobulins Signup and view all the answers

Where do B lymphocytes originate and mature?

Bone marrow Signup and view all the answers

What is the role of the Fc region of an antibody?

Required for antibody function but does not bind antigens Signup and view all the answers

What is the function of the flexible hinge region in antibodies?

It increases the ability of the antibody to bind to multiple epitopes on the same antigen. Signup and view all the answers

What is the primary function of the heavy chain in antibodies?

Mediating effector functions such as complement activation and phagocytosis enhancement. Signup and view all the answers

Which antibody class is primarily responsible for transplacental transport?

IgG Signup and view all the answers

What is the primary function of IgE antibodies?

Degranulation of mast cells and eosinophils. Signup and view all the answers

What is the primary location and function of IgA antibodies?

Mucosal surfaces, prevention of pathogen entry. Signup and view all the answers

What is the primary mechanism that contributes to the diversity of antibodies?

Random recombination of gene segments. Signup and view all the answers

What is the role of the Complementarity Determining Regions (CDRs) in antibodies?

They bind to specific epitopes on the antigen. Signup and view all the answers

Which antibody class is primarily involved in signaling B cell activation?

IgD Signup and view all the answers

What is the primary function of the Fc region in antibodies?

Mediating effector functions like complement activation and phagocytosis. Signup and view all the answers

Which antibody class is primarily involved in the activation of the complement system?

IgM Signup and view all the answers