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T Cells quiz #1 Flashcards

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T Cells quiz #1
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  • What components are required for T cell activation in the adaptive immune system?
    T cell activation requires interaction with antigens presented by antigen presenting cells (APCs) via MHC molecules, co-stimulatory molecules, and cell adhesion molecules.
  • Which cells are responsible for cell-mediated immunity?
    T cells, specifically cytotoxic T cells, are responsible for cell-mediated immunity by directly killing infected cells.
  • What initiates the activation of T cells?
    T cell activation is initiated when T cells interact with antigens presented by antigen presenting cells (APCs) through MHC molecules, along with co-stimulatory and cell adhesion signals.
  • What process do T cell receptors undergo to achieve diversity in antigen recognition?
    T cell receptors undergo VDJ recombination, which rearranges gene segments to create a diverse repertoire of receptors. This allows T cells to recognize a wide variety of antigens.
  • Where do naive T cells first encounter antigens for activation?
    Naive T cells encounter antigens for activation in the thymus, an organ located in the neck and throat region. In the thymus, they interact with antigen presenting cells displaying antigens.
  • What happens to a T cell if it fails to interact with all three required components during activation?
    If a T cell fails to interact with the antigen, co-stimulatory molecules, and cell adhesion molecules, it becomes inactivated or dies. This mechanism prevents inappropriate T cell activation.
  • Which accessory molecule is found on cytotoxic T cells and what does it bind?
    The accessory molecule CD8 is found on cytotoxic T cells. It binds to class I MHC molecules on antigen presenting cells.
  • How do cytotoxic T cells induce death in infected cells?
    Cytotoxic T cells can release perforin to form pores in the target cell or use FAS ligand to trigger apoptosis. Both mechanisms result in the destruction of the infected cell and pathogen.
  • What is the primary function of regulatory T cells in the immune response?
    Regulatory T cells suppress the activity of other T cells to prevent overactive immune responses. They also help prevent autoimmunity by inhibiting self-reactive T cells.
  • Which accessory molecule is present on helper and regulatory T cells, and which MHC class does it interact with?
    Helper and regulatory T cells express the CD4 accessory molecule. CD4 binds to class II MHC molecules on antigen presenting cells.