Functions of Cytotoxic and Suppressor T Cells

Immune System

• Cytotoxic T cells destroy cells infected by viruses, cancer cells, or transplanted organ cells, and are crucial for maintaining osmotic equilibrium in cells.
• Suppressor T cells regulate the activities of other immune cells, preventing excessive immune reactions that could harm the body.

Tolerance Mechanism

• The immune system recognizes self-tissue as distinct from invading organisms, and this recognition develops during T lymphocyte processing in the thymus and B lymphocyte processing in the bone marrow.
• Self-reacting T and B lymphocytes are destroyed due to continuous exposure to self-antigen in the fetus, preventing autoimmune diseases.

Autoimmune Diseases

• Failure of the tolerance mechanism leads to autoimmune diseases, such as rheumatic fever, where the immune system attacks the body's own tissues.

Immunization

• Active immunity can be achieved through injection of dead organisms, toxins treated with chemicals, or live organisms that have been attenuated.
• Passive immunity involves infusing antibodies, activated T cells, or both from an immunized individual or animal, providing temporary protection against disease.

Allergy and Hypersensitivity

• Allergy is an undesirable side effect of immunity, caused by activated T cells or IgE antibodies, leading to skin eruptions, edema, or asthmatic attacks.
• IgE antibodies bind to mast cells and basophils, releasing substances that induce vasodilation, increased capillary permeability, and attraction of neutrophils and eosinophils.
• Examples of allergic reactions include hive (urticaria) and hay fever (allergic rhinitis).

Cell-Mediated Immunity

• Cell-mediated immunity involves the formation of activated T lymphocytes that destroy foreign agents.
• The thymus gland preprocesses T lymphocytes, allowing them to develop diversity in reacting against different antigens.

Thymus Gland

• The thymus gland preprocesses T lymphocytes, allowing them to develop extreme diversity in reacting against different antigens.
• The thymus ensures that T lymphocytes leaving the thymus will not react against the body's own tissues by selecting and releasing only non-self-reacting T lymphocytes.

This quiz covers the roles of cytotoxic and suppressor T cells in the immune system, including their functions in destroying infected cells and regulating immune reactions.