6.2.3 Cell-Mediated Immunity

• What is cell-mediated immunity?

  Elimination of infected cells
• T lymphocytes are key players in cell-mediated immunity
• Antigen-presenting cells (APCs) present antigens to T cells.
• How are cytotoxic T cells (CTLs) activated?

  By antigens via MHC I
• CTLs kill infected cells by releasing enzymes like perforin and granzyme
• Helper T cells (Th cells) play a role in both cell-mediated and humoral immunity.
• What is the function of regulatory T cells (Tregs)?

  Suppression of immune responses
• Steps in the activation of cytotoxic T cells (CTLs)

  1️⃣ APCs present antigens via MHC I

  2️⃣ CTLs identify infected cells

  3️⃣ CTLs release perforin and granzyme

  4️⃣ Target cells undergo apoptosis
• Cytotoxic T cells induce apoptosis in target cells by releasing enzymes like perforin and granzyme
• Memory T cells provide long-term immunity by responding quickly to subsequent exposure to the same antigen.
• Which key cytokines are released in cell-mediated immunity?

  Interleukin-2 and TNF-α
• Helper T cells release cytokines like interleukin-2 and TNF-\alpha</latex> to activate other immune cells
• Match the T-cell type with its function and activation trigger:

  Helper T cells ↔️ Activate immune cells by releasing cytokines; Antigens presented by APCs via MHC II

  Cytotoxic T cells ↔️ Kill infected cells by inducing apoptosis; Antigens presented by target cells via MHC I

  Memory T cells ↔️ Provide long-term immunity by responding to re-exposure; Exposure to previously encountered antigens
• What type of immunity eliminates infected or cancerous cells without using antibodies?

  Cell-mediated immunity
• Helper T-cells release cytokines to activate other immune cells, and their activation is triggered by antigens presented by APCs via MHC II
• Cytotoxic T-cells eliminate infected cells by inducing apoptosis after recognizing antigens via MHC I receptors.
• What is the primary function of memory T-cells?

  Long-term immunity
• Helper T-cells activate cytotoxic T-cells by releasing cytokines like Interleukin-2 and TNF-$\alpha$
• Which type of APC migrates to lymph nodes to activate T-cells?

  Dendritic cells
• Macrophages present antigens via MHC II receptors after phagocytosing pathogens in tissues.
• Helper T-cells enhance cytotoxic T-cell activation by releasing cytokines like Interleukin-2
• Match the T-cell type with its function:

  Helper T-cells ↔️ Activate other immune cells

  Cytotoxic T-cells ↔️ Induce apoptosis in infected cells
• What is the effect of cytotoxic T-cells on target cells?

  Induce apoptosis
• What type of cells present antigens to cytotoxic T cells (CTLs)?

  Antigen-presenting cells
• Helper T-cells release the cytokine Interleukin-2
• Cytotoxic T-cells induce apoptosis in target cells.
• Match the T-cell type with its activation trigger:

  Cytotoxic T-cells ↔️ MHC I receptors

  Helper T-cells ↔️ MHC II receptors
• What is the primary role of cell-mediated immunity?

  Eliminate infected or cancerous cells
• Steps in cell-mediated immunity involving Helper T-cells

  1️⃣ Recognize antigens presented by APCs

  2️⃣ Release cytokines to activate other immune cells

  3️⃣ Stimulate B-cells to produce antibodies

  4️⃣ Activate cytotoxic T-cells
• Cytotoxic T-cells release enzymes like perforin and granzyme
• What is the function of memory T-cells?

  Provide long-term immunity
• Key cytokines in cell-mediated immunity include Interleukin-2 and TNF-$\alpha$.
• How many main types of T lymphocytes are there?

  Three
• Match the T-cell type with its function:

  Helper T-cells ↔️ Activate immune cells

  Cytotoxic T-cells ↔️ Kill infected cells

  Memory T-cells ↔️ Provide long-term immunity
• Cytotoxic T-cells induce apoptosis by releasing enzymes like perforin and granzyme
• What triggers the activation of memory T-cells?

  Exposure to previously encountered antigens
• What are the three main types of T lymphocytes involved in the cell-mediated immune response?

  Helper, Cytotoxic, Memory
• Helper T-cells activate other immune cells by presenting antigens via MHC II
• What is the primary function of cytotoxic T-cells?

  Kill infected cells
• Memory T-cells provide long-term immunity by responding rapidly to previously encountered antigens.