key term - Cell-Mediated Immunity

Definition

Cell-mediated immunity is an immune response that involves the activation of specialized T cells to eliminate pathogens or infected cells. It is a crucial component of the adaptive immune system, working in conjunction with humoral immunity to provide comprehensive protection against a wide range of threats, including viral infections, intracellular bacteria, and certain types of cancer.

5 Must Know Facts For Your Next Test

1. Cell-mediated immunity is the primary defense mechanism against intracellular pathogens, such as viruses and certain bacteria, that can evade humoral immunity.
2. T lymphocytes, particularly cytotoxic T cells, are the key effector cells in cell-mediated immunity, responsible for directly killing infected or cancerous cells.
3. Helper T cells play a crucial role in activating and coordinating the cell-mediated immune response, providing essential signals and support to other immune cells.
4. Cell-mediated immunity is important in defending against viral infections of the skin and eyes, as well as in combating fungal infections (mycoses) of the skin.
5. Impairment of cell-mediated immunity, as seen in conditions like HIV/AIDS, can lead to increased susceptibility to opportunistic infections and certain types of cancer.

Review Questions

• Explain the role of T lymphocytes in cell-mediated immunity and how they contribute to the defense against viral infections of the skin and eyes.
  • T lymphocytes, particularly cytotoxic T cells, are the central effector cells in cell-mediated immunity. They recognize specific antigens presented on the surface of infected or cancerous cells and directly induce their death through the release of cytotoxic granules. In the context of viral infections of the skin and eyes, such as herpes simplex virus or varicella-zoster virus, cytotoxic T cells play a crucial role in identifying and eliminating the infected cells, thereby limiting the spread of the virus and containing the infection.
• Describe how the impairment of cell-mediated immunity can impact the body's ability to combat fungal infections (mycoses) of the skin.
  • Cell-mediated immunity, mediated by T lymphocytes, is essential for defending against fungal infections of the skin, known as mycoses. In conditions where cell-mediated immunity is impaired, such as in HIV/AIDS or certain immunosuppressive treatments, the body's ability to mount an effective response against fungal pathogens is compromised. This can lead to an increased susceptibility to opportunistic fungal infections of the skin, such as dermatophytosis (ringworm), candidiasis, and cryptococcosis. Without the coordinated effort of T cells and other immune cells, these fungal infections may become more prevalent, persistent, and difficult to treat.
• Analyze the interplay between cell-mediated immunity and humoral immunity in providing comprehensive protection against a wide range of threats, including viral infections, intracellular bacteria, and certain types of cancer.
  • Cell-mediated immunity and humoral immunity work in a complementary manner to provide robust and comprehensive protection against a diverse array of threats. While humoral immunity, mediated by antibodies, is effective against extracellular pathogens and toxins, cell-mediated immunity is crucial for targeting intracellular threats, such as viruses and certain bacteria. Cytotoxic T cells, a key component of cell-mediated immunity, can directly recognize and eliminate infected or cancerous cells, preventing the spread of these threats. Meanwhile, helper T cells coordinate and enhance the function of both cell-mediated and humoral immune responses, ensuring a coordinated and effective defense. The synergistic interplay between these two arms of the adaptive immune system is essential for maintaining overall immune competence and protecting the body against a wide range of challenges.

Related terms

T Lymphocytes:

Also known as T cells, these are a type of white blood cell that play a central role in cell-mediated immunity. They develop in the thymus and can directly attack and destroy infected or cancerous cells.

Cytotoxic T Cells:

A subtype of T lymphocytes that are specialized in killing infected or malignant cells. They recognize specific antigens presented on the surface of target cells and release cytotoxic granules to induce cell death.

Helper T Cells:

A subtype of T lymphocytes that coordinate and regulate the immune response. They provide essential signals and support to other immune cells, such as B cells and cytotoxic T cells, to enhance their function.