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T Cells and Cancer - Advanced Immunology

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Termini in questo insieme (21)

  • What is the role of T cells in cancer immunity?
    T cells recognize tumor antigens and can kill tumor cells directly or help coordinate the immune response against cancer.
  • What restricts T cell recognition of antigens?
    T cells recognize antigens as short peptides presented by MHC molecules on target cells, making them MHC-restricted.
  • What are the main subsets of T cells involved in anti-tumor immunity?
    CD8+ cytotoxic T lymphocytes (CTLs) kill tumor cells; CD4+ T helper cells support immune responses and can differentiate into various subsets like Th1 and Tregs.
  • How do cytotoxic T cells kill tumor cells?
    CTLs induce apoptosis in tumor cells by releasing perforin and granzymes and secrete cytokines like IFN-γ and TNF.
  • What is the function of regulatory T cells (Tregs) in cancer?
    Tregs suppress immune responses and maintain peripheral tolerance, often increasing in tumors to help cancer evade immunity.
  • What is immunosurveillance?
    The hypothesis that the immune system patrols tissues to detect and eliminate emerging tumor cells before they form detectable cancers.
  • What are the three phases of cancer immunoediting?
    Elimination: immune destruction of tumor cells; Equilibrium: immune containment of tumor; Escape: tumor evades immune detection and grows.
  • What are tumor-associated antigens (TAAs)?
    Proteins that are overexpressed or aberrantly expressed by tumor cells but may also be present in normal tissues, often weakly immunogenic.
  • What are tumor-specific antigens (TSAs)?
    Antigens derived from mutated proteins or viral sequences unique to tumor cells, often highly immunogenic.
  • How do tumors escape immune recognition?
    By losing antigenicity (e.g., downregulating MHC-I), reducing immunogenicity (inhibiting T cell function), or creating an immunosuppressive microenvironment.
  • What is the significance of HLA-class I loss in tumors?
    Loss or reduction of HLA-class I expression impairs antigen presentation to CD8+ T cells, allowing tumors to evade immune attack.
  • What role does TAP deficiency play in tumor immune escape?
    TAP transports peptides for MHC-I loading; its deficiency reduces antigen presentation, decreasing tumor visibility to CD8+ T cells.
  • How do immune checkpoint receptors regulate T cell function in tumors?
    Checkpoint receptors like PD-1 inhibit T cell activity when engaged by ligands such as PD-L1 on tumor cells, dampening anti-tumor responses.
  • What are some immunosuppressive factors produced in the tumor microenvironment?
    Cytokines like TGF-β, IL-10, enzymes like IDO, and ligands like PD-L1 suppress T cell function and promote tumor growth.
  • What is the role of tumor-infiltrating lymphocytes (TILs)?
    TILs, especially CD8+ T cells, infiltrate tumors and their presence often correlates with better patient prognosis.
  • What are tertiary lymphoid structures (TLS) in tumors?
    TLS are organized immune cell aggregates within tumors that support local T cell activation and are associated with improved survival.
  • What are the main types of T cell-based cancer therapies?
    Checkpoint blockade antibodies, adoptive T cell transfer (including TIL and CAR T cells), and cancer vaccines.
  • How does checkpoint blockade therapy work?
    It blocks inhibitory receptors like PD-1 or CTLA-4 on T cells, releasing the 'brakes' and enhancing anti-tumor immunity.
  • What is adoptive T cell transfer therapy?
    Isolation, expansion, and reinfusion of tumor-specific T cells into patients to boost anti-tumor responses.
  • What is the principle behind cancer vaccines?
    Vaccines aim to stimulate the immune system to recognize tumor antigens and generate effective T cell responses against cancer.
  • Why is patient individualization important in cancer immunotherapy?
    Because tumor antigens and immune responses vary, personalized therapies targeting patient-specific mutations improve efficacy.