T Cells and Thymus Development
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Questions and Answers

Where are precursor cells generated?

  • Spleen
  • Bone marrow (correct)
  • Thymus
  • Liver

    • What chemokine receptor is involved in the migration of precursor cells to the thymus?

  • CXCR4
  • CD117
  • CCR7
  • CCR9 (correct)

    • Which of the following is a stage of T cell maturation in the thymus?

  • PreB formation
  • Bone marrow migration
  • TCRα-rearrangement (correct)
  • Peripheral lymphoid organ differentiation

    • Which type of thymocyte is referred to as 'double negative'?

    <p>CD4-CD8-</p> Signup and view all the answers

    What do the markers c-Kit and IL-7R indicate in early thymocyte precursors (ETP)?

    <p>Progenitor status</p> Signup and view all the answers

    After maturation, where do mature T cells migrate?

    <p>Peripheral lymphoid organs and then to various organs after infection</p> Signup and view all the answers

    What is the importance of cyclin function in thymocyte maturation?

    <p>It regulates quality control processes.</p> Signup and view all the answers

    Which of the following thymocyte subsets are considered 'double positive'?

    <p>CD4+CD8+</p> Signup and view all the answers

    What is the natural host for the lymphocytic choriomeningitis virus (LCMV)?

    <p>Rodents</p> Signup and view all the answers

    What type of virus is the lymphocytic choriomeningitis virus (LCMV)?

    <p>Segmented ssRNA virus</p> Signup and view all the answers

    What is a common symptom experienced by healthy adults infected with LCMV?

    <p>Flu-like symptoms</p> Signup and view all the answers

    Which CD8 T cell epitope is identified as the dominant epitope in C57BL/6 mice for LCMV?

    <p>GP33-41</p> Signup and view all the answers

    What risk is associated with LCMV infection for pregnant women?

    <p>Risk of miscarriage</p> Signup and view all the answers

    What is the transmission route for LCMV?

    <p>Organ transplants and birth</p> Signup and view all the answers

    LCMV does not directly destroy cells because it is considered what type of virus?

    <p>Non-cytopathic</p> Signup and view all the answers

    What is the serum prevalence of LCMV in humans?

    <p>5-10%</p> Signup and view all the answers

    What is the consequence of a lack of co-stimulation in T cells?

    <p>Anergy</p> Signup and view all the answers

    Which molecules are primarily involved in forming the immunological synapse?

    <p>TCR and MHC</p> Signup and view all the answers

    What characterizes the c-SMAC within the immunological synapse?

    <p>It includes 400-700 TCR molecules.</p> Signup and view all the answers

    What do Rag1 and Rag2 specifically cleave during VDJ recombination?

    <p>Recombination signal sequences (RSS)</p> Signup and view all the answers

    What is the primary function of Ku70 and Ku80 in the repair of coding joints?

    <p>They stabilize DNA double strand breaks.</p> Signup and view all the answers

    What is the role of CD8 T cells in the immune response?

    <p>Killing virus-infected cells and tumor cells</p> Signup and view all the answers

    Which substances do activated CD8 T cells secrete to induce apoptosis in target cells?

    <p>Perforin and Granzyme B</p> Signup and view all the answers

    Which sequences are brought together by Rag1 and Rag2 during the VDJ recombination?

    <p>12nt and 23nt sequences</p> Signup and view all the answers

    What triggers the differentiation of naive T cells into activated T cells?

    <p>Co-stimulation from accessory cells</p> Signup and view all the answers

    What role does TdT play in the repair of coding joints?

    <p>It adds N-nucleotides to the open DNA ends.</p> Signup and view all the answers

    In which location do naive CD8 T cells typically become activated?

    <p>Lymph nodes</p> Signup and view all the answers

    Which protein complex is involved in the ligation of DNA ends during coding joint repair?

    <p>DNA ligase IV and XRCC4</p> Signup and view all the answers

    What is a key feature of the dynamic process of immunological synapse formation?

    <p>It involves continuous rearrangement of molecular components</p> Signup and view all the answers

    What are the short sequences that cause bending of the DNA during VDJ recombination known as?

    <p>Recombination signal sequences (RSS)</p> Signup and view all the answers

    What modification occurs to the joint region during VDJ recombination?

    <p>Addition of P- and N-nucleotides</p> Signup and view all the answers

    What happens to the hairpin structure during coding joint repair?

    <p>It is opened by Artemis.</p> Signup and view all the answers

    What is the role of phospholipase C-gamma (PLC-γ) in T cell activation?

    <p>It generates signals by cleaving phospholipids in the membrane.</p> Signup and view all the answers

    Which signal is primarily dependent on IL-2 for T cell proliferation?

    <p>Signal 3</p> Signup and view all the answers

    What occurs if T cells receive only Signal 1 during activation?

    <p>Anergy occurs.</p> Signup and view all the answers

    Which component is NOT involved in the signaling cascade following T cell receptor activation?

    <p>TLR</p> Signup and view all the answers

    What is the function of B7 (CD80, CD86) in T cell activation?

    <p>To deliver a co-stimulatory signal.</p> Signup and view all the answers

    Which kinases are involved in the phosphorylation of the immunoreceptor tyrosine-based activation motif (ITAM)?

    <p>Lck and Fyn</p> Signup and view all the answers

    Which of the following is a consequence of T cell activation related to NFκB, NFAT, and AP-1?

    <p>Enhanced production of IL-2.</p> Signup and view all the answers

    What is the primary role of DAG in T cell signaling?

    <p>To serve as a second messenger for PKC activation.</p> Signup and view all the answers

    What is the primary function of CD4 T cells?

    <p>Provide helper functions for B cells, macrophages, and CD8 T cells</p> Signup and view all the answers

    Which cytokine is primarily associated with inducing IgE in B cells?

    <p>IL-4</p> Signup and view all the answers

    What is required for naive T cell activation?

    <p>Three distinct signals</p> Signup and view all the answers

    What type of T cells recognize peptide antigens in MHC-I molecules?

    <p>CD8 T cells</p> Signup and view all the answers

    Which cytokine is mainly involved in co-stimulation during T cell activation?

    <p>B7</p> Signup and view all the answers

    What is the outcome if naive T cells do not receive proper activation signals?

    <p>They become anergic</p> Signup and view all the answers

    Which T cell receptor chains are involved in forming the TCR?

    <p>Either alpha/beta or gamma/delta chains</p> Signup and view all the answers

    What role does IFN-γ play in the immune response?

    <p>Induces macrophage activation</p> Signup and view all the answers

    Study Notes

    • T cells develop and mature in the thymus
    • T cells are crucial for adaptive immunity
    • T cells have specific functions for development and subsets
    • T cells recognize antigens, and execute effector functions
    • Hematopoiesis is the production of blood cells, and T cells originate from the common lymphoid progenitor
    • Adaptive immune system's evolution varies across species (from fish to humans)
    • The thymus organogenesis process involves the formation of the thymus from pharyngeal pouches
    • The thymus is crucial for T cell development, and its size peaks in puberty
    • Foxn1 is essential for thymic development, and mutations lead to a thymus-less condition
    • T cells mature in the thymus, following migration to peripheral lymphoid organs
    • T cell maturation involves distinct stages that maintain quality control
    • TCRs undergo rearrangement (αβTCR or γδTCR)
    • TCR diversity is enormous due to combinatorial mechanisms during development
    • The 12-23 rule governs VDJ recombination, ensuring proper pairing of gene segments and resulting in huge diversity of TCRs
    • Rag1 and Rag2 recombinases cleave DNA at specific sequences to create TCR diversity
    • The DNA double-strand breaks are stabilized, with N- and P-nucleotides added to coding joints
    • MHC molecules present peptides that are generated from intracellular or extracellular antigens , and this is essential for presenting and recognition by T cells
    • Different T cell subsets have varying roles in adaptive immune responses
    • CD8 T cells (cytotoxic T cells) are involved in killing virus-infected cells and cancer cells
    • Antigen recognition by T cells involves CD4 or CD8 T cell receptor (TCR) interacting with major histocompatibility complex (MHC) molecules that are peptide-bound
    • Different MHC classes present different peptide types to T lymphocytes (e.g. MHC I and MHC II)
    • MHC genes exhibit high polymorphism and co-dominance, presenting diverse peptides to T cells for recognition
    • T cell activation requires three signals including TCR-MHC peptide recognition, co-stimulation and cytokines
    • Antigen-presenting cells (APCs) such as dendritic cells are vital in activation of T cells, and present antigens to them
    • T cell anergy occurs when T cells do not receive co-stimulation, which can prevent inappropriate activation
    • The immunological synapse is the zone of contact that develops between T cells and antigen-presenting cells (APCs).
    • A T cell receptor (TCR) docks with the MHC molecule to allow recognition
    • T cells help in immune responses to viruses and other pathogens
    • Many different kinds of T cells can develop in response to distinct challenges

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    Adaptive Immunity (I) PDF

    Description

    Explore the intricate processes involved in T cell development and maturation within the thymus. This quiz covers topics such as hematopoiesis, T cell receptor diversity, and the evolutionary significance of the adaptive immune system. Test your knowledge on the crucial role of the thymus and the factors influencing T cell functionality.

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