Basics of the Immune System
- The immune system defends the body against pathogens like viruses, bacteria, and harmful molecules.
- Key players: T cells, a type of white blood cell, coordinate immune responses and destroy infected cells.
- Problem: How does the immune system avoid attacking the body’s own healthy cells? This is called immune tolerance.
Relevance
- GS-3 (Science & Technology):
- Advances in immunology and biotechnology
- Implications for healthcare, personalized medicine, and public health
- GS-2/3 (Ethics & Innovation):
- Research ethics, translational research, and equitable access to advanced therapies
The Discovery
- By the 1980s, scientists hypothesized the existence of a special type of T cell that prevents the immune system from attacking itself.
- These were later identified as regulatory T cells (Tregs), also known as “police” T cells.
- Function of Tregs:
- Suppress overactive immune responses.
- Maintain tolerance to self-antigens.
- Prevent autoimmune diseases (conditions where the body attacks itself).
Key Experiments
- Shimon Sakaguchi’s study (1995):
- Surgically removed the thymus (T cell maturation site) in newborn mice.
- Result: Mice developed autoimmune conditions unless Tregs were present.
- Conclusion: Thymus is crucial for producing regulatory T cells; without them, self-attack occurs.
- Later experiments identified FOXP3 gene as essential for Treg development.
- Mutations in FOXP3 → autoimmune conditions like IPEX syndrome in humans and Scurfy mice in animals.
Contributions of Researchers
- Shimon Sakaguchi (Japan):
- Discovered Tregs and their role in immune tolerance.
- Coined the term “police T cells.”
- Mary F. Brunkow & Frederick J. Ramsdell (USA):
- Identified the FOXP3 gene controlling Treg development.
- Linked genetic mutations to autoimmune diseases in humans.
Significance of Regulatory T Cells
- Autoimmunity: Prevents the immune system from attacking organs and tissues.
- Cancer therapy:
- Some therapies target Tregs to enhance immune attacks on tumors.
- Understanding Tregs helps balance immune activation and suppression.
- Drug development: Potential to create therapies for autoimmune diseases by modulating Treg activity.
- Gene therapy: FOXP3 gene research enables interventions in rare immune disorders.
Why This Is in the News
- 2025 Nobel Prize in Physiology or Medicine awarded to Sakaguchi, Brunkow, and Ramsdell.
- Recognises the decades-long work in immune tolerance and regulatory T cell biology.
- Implications for:
- Understanding autoimmune diseases.
- Development of immunotherapies for cancer.
- Potential future therapies to balance immune overactivity.
- Highlights the integration of genetics, immunology, and therapeutic innovation.
Bottom Line
- Regulatory T cells are the body’s internal “police”, ensuring that immune responses target invaders but not healthy cells.
- Discovery of these cells and their genetic control mechanisms has transformed:
- Basic immunology.
- Clinical management of autoimmune conditions.
- Precision medicine approaches in cancer therapy.
