40 Questions
What is the main purpose of Igα and Igβ in B lymphocytes?
To initiate the process of B cell activation
Which molecules combine with the membrane Ig to make up the BCR complex?
Igα and Igβ
What is the significance of monoclonal antibodies in immunology?
They have far-reaching applications in clinical medicine and research
What is the process used to produce monoclonal antibodies?
Obtaining B cells from an animal immunized with an antigen and fusing them with myeloma cells
What type of cells are formed from the fusion of myeloma and normal B cell nuclei?
Hybrid cells
Which type of cells produce antibodies like normal B cells?
Hybridomas
What is the main advantage of monoclonal antibodies produced from hybridomas?
Homogeneous antibodies
In the production of monoclonal antibodies, what cells are fused with an enzyme-deficient myeloma cell line?
Spleen cells from a mouse immunized with an antigen
What issue is partially overcome by humanized antibodies?
Immune response to mouse Ig
What kind of molecules does T Cell Receptor (TCR) recognize?
Peptide antigens displayed by Major Histocompatibility Complex (MHC) molecules
What is the composition of TCR (T Cell Receptor)?
A membrane-bound heterodimeric protein composed of an α chain and a β chain
What is the function of associated proteins (CD3 and ζ) and coreceptors (CD4 or CD8) in T Cell Receptor (TCR) function?
Signal initiation and MHC recognition
What is the most variable region among different TCRs?
CDR3
How do TCR and B cell receptor (antibodies) differ?
Antigen recognition, affinity, and structure
What type of cells recognize both MHC molecules and bound peptides for antigen specificity and restriction?
TCR (T Cell Receptor)
Which type of antibodies are widely used as therapeutic and diagnostic agents?
Monoclonal antibodies
During B cell maturation, which of the following gene segments recombines with a J segment to form a DJ complex?
D segment
Which enzyme mediates the somatic recombination of V and J, or of V, D and J, gene segments?
VDJ recombinase
Which part of the VDJ recombinase recognizes the heptamer sequences?
RAG-1 protein
Which gene segments are lacking in the light-chain loci, leading to direct recombination of a V region gene segment with a J segment?
D segments
Which gene segments are responsible for forming a complete μ messenger RNA (mRNA) in B cells?
VDJ exon and C-region exons
Which cells express intact Ig heavy-chain and light-chain genes?
B cells
Which gene segments are found in the Ig kappa chain locus?
V, J, C
Which chain locus contains L, V 1, L V n, J 1, C 1, J 2, C 2, J 3, C 3, J 7, and C 7?
Ig lambda chain locus
Which statement is true regarding TCR alpha and beta genes?
Expressed only in T cells
What is the function of the VDJ recombinase in mature lymphocytes?
Expresses intact Ig heavy-chain and light-chain genes
Which subset of T cells express γ and δ chains, forming receptors with unique specificities that can recognize a variety of antigens, including non-protein antigens?
Natural killer T (NK-T) cells
What is the function of mucosal associated invariant T (MAIT) cells?
Recognize bacterially derived vitamin B metabolites bound to an MHC-like protein
What is the distinguishing feature of TCRs compared to membrane antibodies?
Both chains are anchored in the plasma membrane
Which type of cells account for 5-10% of T cells and express γ and δ chains?
MAIT cells
What is the main characteristic of T cells expressing both αβ TCRs and surface molecules of natural killer cells?
Recognize lipid antigens displayed by CD1
What is the approximate percentage of MAIT cells among liver T cells in humans?
40%
Which subset of T cells recognize bacterially derived vitamin B metabolites bound to an MHC-like protein called MR1?
MAIT cells
What is the specific function of γδ cells, NK-T cells, and MAIT cells?
Not well understood
Which developmental stage involves the activation of specific transcription factors and increased gene accessibility?
Commitment to B or T cell lineage
Where do B and T lymphocytes mature despite undergoing similar developmental processes?
Bone marrow for B cells, thymus for T cells
What stimulates survival and proliferation of earliest lymphocyte precursors?
Growth factors produced by stromal cells
What is necessary for survival and progenitors' proliferation during lymphocyte development?
Functional antigen receptors
How is diversity generated in Ig and TCR genes?
Through somatic recombination
What eliminates self-reactive or non-functional cells during lymphocyte development?
Selection processes
Study Notes
- Lymphocyte development involves the commitment of hematopoietic progenitors to B or T cell lineage, proliferation, gene rearrangement, and selection.
- B and T lymphocytes undergo similar developmental processes despite maturing in different locations (bone marrow for B cells, thymus for T cells).
- Commitment to B or T cell lineage is associated with the activation of specific transcription factors and increased gene accessibility.
- Proliferation of developing lymphocytes occurs at multiple stages and is necessary for generating a diverse pool of cells.
- Growth factors produced by stromal cells stimulate survival and proliferation of earliest lymphocyte precursors.
- Gene rearrangements randomly generate diverse antigen receptor specificities.
- Selection processes allow only useful specificities to fully mature, eliminating self-reactive or non-functional cells through positive and negative selection.
- Functional antigen receptors are necessary for survival and progenitors' proliferation, while cells that fail to express them undergo apoptosis.
- Ig and TCR genes are inherited in a germline configuration, and diversity is generated through somatic recombination.
- Each Ig and TCR gene locus contains multiple V region gene segments and one or a few C region genes.
Test your knowledge of T cell receptor (TCR) characteristics with this quiz. Learn about the differences between TCRs and membrane antibodies, TCR chain anchoring, TCR production, and the unique features of γδ TCRs.
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