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Adaptive Immunity - T Cells and Antigens

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Terms in this set (29)

  • Another name for CD4 T cells

    Helper T cells

  • Another name for CD8 T cells

    Cytotoxic T cells

  • What are immunogens?

    Substances that provoke an immune response by stimulating lymphocytes.

  • What are haptens?

    Small molecules that are not immunogenic alone but can trigger an immune response when attached to a larger carrier.

  • What are exogenous antigens?

    Antigens that originate outside the body, such as pathogens or toxins.

  • What are endogenous antigens?

    Antigens generated within the body, typically from infected or abnormal cells.

  • What antigens can be considered endogenous?

    Antigens from viruses or intracellular bacteria produced inside host cells.

  • Steps to T cell formation

    Origin in bone marrow, migration to thymus, positive and negative selection, maturation, and release to circulation.

  • What do T cell receptors bind to?

    Antigen fragments presented by Major Histocompatibility Complex (MHC) molecules

  • What does the thymus screen for during T cell development?

    T cells that recognize self-antigens too strongly are eliminated to prevent autoimmunity.

  • Why do Major Histocompatibility Complex (MHC) molecules exist?

    To present antigen fragments to T cells for immune recognition.

  • Two classes of MHC molecules

    Class I MHC and Class II MHC

  • Where are Class I MHC molecules found and what antigen do they present?

    On all nucleated cells; present endogenous antigens to CD8 (cytotoxic) T cells.

  • Where are Class II MHC molecules found and what antigen do they present?

    On antigen-presenting cells (APCs); present exogenous antigens to CD4 (helper) T cells.

  • What is clonal selection?

    The process where specific T cells recognizing an antigen proliferate to fight the pathogen.

  • What are co-stimulators?

    Molecules required alongside antigen recognition to fully activate T cells.

  • What are effector cells?

    Activated T cells that perform functions like killing infected cells or helping other immune cells.

  • What are memory T cells?

    Long-lived T cells that provide faster response upon re-exposure to the same antigen.

  • What is cross-presentation?

    Process where exogenous antigens are presented on Class I MHC molecules to activate CD8 T cells.

  • Role of Helper T cells

    Activate other immune cells by releasing cytokines and enhancing immune responses.

  • Role of Cytotoxic T cells

    Directly kill infected or abnormal cells presenting antigen on Class I MHC.

  • What does perforin do?

    Protein released by cytotoxic T cells that creates pores in target cell membranes to induce cell death.

  • Four basic kinds of grafts

    Autograft, isograft, allograft, and xenograft.

  • Describe an autograft

    Graft transplanted from one site to another on the same individual.

  • Describe an isograft

    Graft between genetically identical individuals, such as identical twins.

  • Describe an allograft

    Graft between genetically different members of the same species.

  • Describe a xenograft

    Graft between different species.

  • Which gene must match for a proper skin transplant?

    The Major Histocompatibility Complex (MHC) gene.

  • What is necrosis?

    Uncontrolled cell death causing tissue damage and inflammation.