57 Questions
What is the primary function of the Fc region of an antibody?
Determining the range of functions facilitated by the antibody
What is the primary mechanism by which antibodies facilitate phagocytosis?
Opsonisation of pathogens
During B cell development, when does the initial generation of diversity occur?
As the cells are first formed, before exposure to exogenous antigen
What is the primary function of antibody-dependent cell-mediated cytotoxicity (ADCC)?
Marking infected cells for destruction by immune cells
What is the primary role of antibodies in the context of pathogens?
To recognise and bind to whole pathogens
What is the primary goal of having a diverse repertoire of lymphocytes in the adaptive immune system?
To increase the chance of finding a match to the pathogen
What is the main difference between T cell receptors and B cell receptors?
T cell receptors are associated with the MHC, while B cell receptors are not
What is the primary function of the germinal center in B cell activation?
To activate T cell help and facilitate isotype class-switching
What is the term for the process by which B cells change the isotype of their antibody while maintaining the same antigen specificity?
Isotype class-switching
What is the main difference between T-dependent and T-independent B cell responses?
T-dependent responses require T cell help, while T-independent responses do not
What is the primary function of B cells in the adaptive immune system?
To recognize antigens on whole molecules
What are the enzymes responsible for recombination of immunoglobulin genes?
RAG1 and RAG2
What is the combination of gene segments used to form the heavy chain of an antibody?
VJ or VDJ depending on the chain
How many proteins can be encoded by the IGHV regions if each protein is encoded by a single gene?
9 proteins
What is the purpose of gene rearrangement in immunoglobulin genes?
To generate diversity in antibody production
How many proteins can be encoded by the IGHV regions if each protein is encoded by a combination of group 1, group 2, and group 3?
24 proteins
What is the composition of the light chain of an antibody?
VJ and kappa or lambda light chain
Where does the gene rearrangement of T cell receptors occur?
Thymus
What is required for both affinity maturation and class switching in B cells?
AID enzyme and T helper cells
Which type of antigen does not require reference to a specific receptor for activation?
T-independent type I
What is the result of cross-linking of multiple receptors on the B cell surface?
Activation of the B cell
Which cells are involved in providing cytokine help to B cells during T-independent type II activation?
Dendritic cells
What is the name of the enzyme required for both affinity maturation and class switching in B cells?
AID (Activation Induced Cytidine Deaminase)
What is the primary function of CD40-CD40L signaling in T-dependent B cell development?
B cell proliferation and differentiation
What is the role of TCR 'Signal 1' in B-T cell interactions?
Activation of the T cell receptor
Which chemokines are involved in the development of the germinal center?
CXCL12 and CXCL13
What is the primary function of B cells in T-dependent protein antigen responses?
Antigen presentation to T cells
What is the outcome of CD40-CD40L signaling in T-dependent B cell development?
Isotype switching and B cell differentiation
Gene rearrangement occurs in the Bursa Fabricus in chickens.
False
The Fc region of an antibody determines the antigen specificity.
False
Class switching occurs through gene rearrangement.
False
B cell receptors can recognize peptide antigen presented to it by MHC on other cells.
False
The human genome has enough genes to create a unique antibody for every possible pathogen.
False
Isotype class-switching, somatic hypermutation, and affinity maturation are all mechanisms to generate a diverse repertoire of lymphocytes.
False
The VDJ gene rearrangement is responsible for creating the light chain of an antibody.
False
Heterodimer formation occurs in B cell receptor structure.
False
T cell help is required for the activation of B cells in T-independent B cell responses.
False
The primary function of B cells is to provide cytokine help to T cells during T-dependent B cell responses.
False
The germinal center is a location where B cells undergo initial generation of diversity.
False
The Fc region of an antibody determines its antigen specificity.
False
The RAG1 and RAG2 enzymes are responsible for the rearrangement of T cell receptors.
False
The combination of gene segments used to form the light chain of an antibody is VDJ.
False
The IGHV regions can encode up to 9 proteins if each protein is encoded by a single gene.
True
The gene segments used to form the heavy chain of an antibody are V, D, and J.
True
The gene rearrangement of immunoglobulin genes occurs in the germinal center.
False
The mathematics of combinatorial diversity allows for the generation of up to 24 proteins from the IGHV regions.
True
The number of different Ig gene possibilities is exactly 5 million due to the junctional region diversity.
False
Class switching involves changing the antigen specificity in the Variable region.
False
IgM is a membrane-bound form of Immunoglobulin on Naïve B cells.
True
The Fc region enables the molecules to diffuse into tissues or cross the placenta.
False
The enzyme TdT is responsible for randomly removing nucleotides from the J region.
False
The human immune system can produce approximately 1 million different antibodies.
False
B cells process the protein and present the peptide antigen on the surface with MHC class I molecules in order to recruit T cell help for the response.
False
CD40-CD40L signaling is involved in the inhibition of cell death in B cells.
True
T-independent B cell responses do not require reference to a specific receptor for activation.
False
Memory B cells are formed during T-independent B cell responses.
False
The Germinal Centre is involved in isotype switching and affinity maturation of B cells.
True
Study Notes
- B cells process protein antigens and present peptide antigens on their surface with MHC class II molecules to recruit T cell help for the response.
- Memory B cells are formed, and B-T interactions involve the B cell receptor capturing antigen to present to the T cell, up-regulation of co-stimulatory molecules, and TCR "Signal 1".
- The T cell provides helpful signals to the B cell, including "Signal 2", which involves TNF-R family molecules, contributing to CD40 B cell proliferation, differentiation, isotype switching, and upregulation of surface molecules.
- Germinal centre development occurs, involving inhibition of cell death, and CD40 ligand plays a role in T-dependent B cell development.
- A diverse repertoire of lymphocytes is created through gene rearrangement and heterodimer formation, allowing for a vast number of possible antibody combinations.
- B cell receptors recognise whole antigens on the surface of pathogens, whereas T cell receptors recognise peptide antigens presented by MHC on other cells.
- There are three types of antigen that can activate B cells: T-independent type I (TI-I), T-independent type II (TI-II), and T-dependent (TD).
- T-independent type I (TI-1) antigens are polyclonal activators that stimulate B cells without the need for specific receptor recognition, whereas T-independent type II (TI-2) antigens are large molecules with repeating determinants that bind to multiple receptors on the cell surface.
- T-dependent antigens require T cell help and involve the activation of B cells through the germinal centre, leading to the formation of memory B cells.
- Antibodies play a crucial role in the immune response, neutralising toxins and viruses, opsonising pathogens, activating the complement cascade, agglutinating particles, and mediating antibody-dependent cell-mediated cytotoxicity (ADCC).
Test your understanding of the adaptive immune response, including the generation of diversity in lymphocytes, the functions of antibodies, and the activation and maturation of B cells. This quiz covers T-dependent and T-independent B cell responses, the role of T cell help, and the germinal centre.
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