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Questions and Answers
Which of the following cytokines is NOT produced by Th17 cells?
Which of the following cytokines is NOT produced by Th17 cells?
Which of the following is NOT a function of Treg cells?
Which of the following is NOT a function of Treg cells?
Which type of T cell primarily helps B cells to produce antibodies?
Which type of T cell primarily helps B cells to produce antibodies?
Which of the following is NOT a cytokine produced by Th1 cells?
Which of the following is NOT a cytokine produced by Th1 cells?
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Which type of T cell primarily helps CD8+ T cells become cytotoxic?
Which type of T cell primarily helps CD8+ T cells become cytotoxic?
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Which of the following cytokines is NOT directly involved in the differentiation of naïve CD4+ T cells into effector T cell subtypes?
Which of the following cytokines is NOT directly involved in the differentiation of naïve CD4+ T cells into effector T cell subtypes?
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Which type of effector T cell primarily contributes to the suppression of immune responses?
Which type of effector T cell primarily contributes to the suppression of immune responses?
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Which of the following is NOT a mechanism by which Treg cells suppress immune responses?
Which of the following is NOT a mechanism by which Treg cells suppress immune responses?
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Which molecules are involved in presenting peptides to T cells?
Which molecules are involved in presenting peptides to T cells?
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What is the total number of signals required for T cell activation?
What is the total number of signals required for T cell activation?
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What type of T cells are classified as cytotoxic lymphocytes?
What type of T cells are classified as cytotoxic lymphocytes?
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Which of the following correctly represents the structure of MHC class I?
Which of the following correctly represents the structure of MHC class I?
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What do CD4+ T cells primarily recognize?
What do CD4+ T cells primarily recognize?
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Which term best describes the genes encoding MHC class I and II molecules?
Which term best describes the genes encoding MHC class I and II molecules?
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What is the function of co-stimulatory molecules during T cell activation?
What is the function of co-stimulatory molecules during T cell activation?
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Which subtype of T cell is primarily involved in helping B cells and CD8+ T cells?
Which subtype of T cell is primarily involved in helping B cells and CD8+ T cells?
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What type of signal is recognized by the T cell receptor (TCR)?
What type of signal is recognized by the T cell receptor (TCR)?
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Which cells express MHC class II molecules?
Which cells express MHC class II molecules?
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Study Notes
T Cell Antigen Recognition
- Peptides are displayed by cells in the context of highly polymorphic MHC molecules
- T cells recognize peptides with their T cell receptors
MHC Molecules
- MHC I:
- Associates with β2 microglobulin
- Expressed on all nucleated cells
- Displays peptides from endogenously expressed proteins
- MHC II:
- Expressed on specialized antigen-presenting cells (APCs): monocytes, macrophages, dendritic cells, and B lymphocytes
- Displays peptides from exogenously derived proteins
Sources of Peptides Loaded into MHC Class I and II
- MHC class I: viruses and other intracellular pathogens
- MHC class II: extracellular pathogens and proteins
Structure and Function of MHC Molecules
- Highly polymorphic genes encoding MHC class I and II
- MHC molecules are heterodimers (α and β chains) for MHC I and II
T Cell Receptors (TCRs)
- T cells are defined by expression of the T cell receptor
- TCRs are membrane-bound heterodimers (α and β chains) with variable and constant domains
- TCR genes undergo rearrangements from germline before translation
- Two subtypes: αβ and γδ
T Cell Activation
- Activation of T cells requires two signals: Signal 1 (TCR-MHC interaction) and Signal 2 (co-stimulation)
- Co-stimulatory molecules (CD28 and CD86) are upregulated on APCs by 'danger signals' (infection and inflammation)
CD8 T Cells
- Recognize peptides presented by MHC I
- Cytotoxic T cells that can kill target cells (virally infected or cancerous cells)
CD4 T Cells
- Recognize peptides presented by MHC II
- Can differentiate into different kinds of effector T cells with distinct functions:
- Th1: produce IFN-γ and help activate CD8 T cells and macrophages
- Th2: produce IL-4 and help activate B cells
- Th17: produce IL-17 and help fight extracellular pathogens
- Treg: suppress immune responses and maintain self-tolerance
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Description
A comprehensive quiz covering lectures 2-5 of immunology, including innate immune response, antibody diversity, lymphocytes, T cells, MHC, and tolerance.
