Table of contents

1. Introduction to Anatomy & Physiology5h 43m
2. Cell Chemistry & Cell Components12h 36m
3. Energy & Cell Processes10h 6m
4. Tissues & Histology10h 3m
5. Integumentary System2h 20m
6. Bones & Skeletal Tissue2h 16m
7. The Skeletal System2h 35m
8. Joints2h 17m
9. Muscle Tissue2h 33m
10. Muscles1h 11m
11. Nervous Tissue and Nervous System1h 35m
12. The Central Nervous System1h 6m
- Introduction to the Central Nervous System
  18m
- The Cerebrum
  48m
13. The Peripheral Nervous System1h 26m
14. The Autonomic Nervous System1h 38m
15. The Special Senses2h 41m
16. The Endocrine System2h 48m
17. The Blood3h 22m
18. The Heart3h 42m
19. The Blood Vessels3h 35m
20. The Lymphatic System3h 16m
21. The Immune System14h 37m
22. The Respiratory System3h 20m
23. The Digestive System2h 5m
24. Metabolism and Nutrition4h 0m
25. The Urinary System2h 39m
26. Fluid and Electrolyte Balance, Acid Base Balance37m
27. The Reproductive System2h 5m
28. Human Development1h 21m
29. Heredity3h 32m

21. The Immune System

Functions of T Lymphocytes

Anatomy & Physiology

21. The Immune System

Functions of T Lymphocytes

Previous problemNext problem

4:09 minutes

Problem 19

Textbook Question

Describe the specific roles of helper, cytotoxic, and regulatory T cells in cell-mediated immunity. Which is thought to be disabled in AIDS?

Verified step by step guidance

Helper T cells (CD4+ T cells) play a central role in cell-mediated immunity by activating other immune cells. They release cytokines to stimulate the activity of cytotoxic T cells and B cells, enhancing the immune response.

Cytotoxic T cells (CD8+ T cells) are responsible for directly attacking and destroying infected cells, cancer cells, or foreign cells. They recognize antigens presented by infected cells and induce apoptosis (programmed cell death) in these target cells.

Regulatory T cells (Tregs) help maintain immune system balance by suppressing excessive immune responses. They prevent autoimmune reactions by ensuring the immune system does not attack the body's own tissues.

In AIDS (Acquired Immunodeficiency Syndrome), helper T cells (CD4+ T cells) are specifically targeted and destroyed by the HIV virus. This leads to a weakened immune system, as the activation and coordination of other immune cells are compromised.

The loss of helper T cells in AIDS results in a reduced ability to fight infections and diseases, making the body vulnerable to opportunistic infections and certain cancers.

Verified video answer for a similar problem:

This video solution was recommended by our tutors as helpful for the problem above

Video duration:

Play a video:

Was this helpful?

Key Concepts

Here are the essential concepts you must grasp in order to answer the question correctly.

Helper T Cells

Helper T cells, or CD4+ T cells, play a crucial role in the immune response by activating other immune cells, including B cells and cytotoxic T cells. They release cytokines that enhance the immune response, helping to coordinate the body's defense against pathogens. Their proper functioning is essential for a robust immune system.

Cytotoxic T Cells

Cytotoxic T cells, or CD8+ T cells, are responsible for directly killing infected or cancerous cells. They recognize specific antigens presented by infected cells and release perforins and granzymes to induce apoptosis in these target cells. This action is vital for controlling infections and eliminating tumor cells.

Regulatory T Cells

Regulatory T cells, or Tregs, help maintain immune tolerance and prevent autoimmune responses by suppressing the activity of other immune cells. They play a critical role in modulating the immune response to ensure it is appropriate and not overly aggressive. In the context of AIDS, the depletion of helper T cells impairs the overall immune response, including the function of regulatory T cells.

Watch next

Master Functions of Cytotoxic T Cells with a bite sized video explanation from Bruce Bryan

Start learning