2025 Nobel Prize in Physiology or Medicine Awarded
Why focus: Nobel in Medicine for Regulatory T cells — perfect GS3 Sci-Tech proxy for human immune system concepts linked to NCERT Class 12 Biology.
In News
What Happened
Why It Matters
Background
History & Context
What Changed
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BEFORE: Central immune tolerance (thymic deletion of immune cells) was considered the only major mechanism for preventing autoimmunity. NOW: Peripheral immune tolerance, mediated actively by regulatory T cells (Tregs) circulating in the body, is recognized as an essential, ongoing mechanism.
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BEFORE: The genetic cause of the fatal autoimmune condition in 'scurfy' mice and the severe human IPEX syndrome was a complete mystery. NOW: The FOXP3 gene was identified as the direct genetic driver, proving that a single gene mutation can dismantle immune tolerance.
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BEFORE: Immune system T cells were broadly understood as either 'helpers' (CD4+) or 'killers' (CD8+) that activate to fight pathogens. NOW: A distinct subset of 'suppressor' or regulatory T cells (CD4+CD25+FOXP3+) is known to actively dampen and turn off immune reactions.
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BEFORE: Cancer and autoimmune therapies largely relied on broad, systemic immunosuppression or non-specific stimulation. NOW: Targeted therapies are being developed to precisely inhibit Tregs (allowing the immune system to destroy cancer cells) or boost Tregs (to treat autoimmune diseases and prevent organ transplant rejection).
What Did NOT Change
Despite these targeted discoveries, the fundamental reality that the immune system must continuously balance attack and tolerance remains the same. Additionally, while Treg-specific therapies have entered clinical trials, traditional broad immunosuppressive drugs are still widely used as the standard of care for many autoimmune conditions.
Prelims Angle
NCERT Connection
Common Misconceptions
✗ T cells are exclusively involved in attacking foreign pathogens or virally infected cells.
✓ A specific subset called Regulatory T cells (Tregs) actively suppress the immune response and prevent other T cells from attacking healthy host tissues.
Basic biology education heavily focuses on Cytotoxic T cells (killers) and Helper T cells, often omitting the suppressive role of Tregs.
✗ The body prevents autoimmunity only by destroying bad immune cells before they mature in the thymus.
✓ Self-reactive immune cells frequently escape the thymus, but peripheral tolerance via Tregs keeps them in check in the bloodstream and tissues.
Central tolerance (in the thymus) is an older, easier-to-teach concept, leading to the assumption that peripheral checkpoints do not exist.
Practice Questions
Q1
How Many CorrectConsider the following statements regarding Regulatory T cells (Tregs) and peripheral immune tolerance: 1. Shimon Sakaguchi discovered that Tregs actively suppress the immune system to prevent autoimmune diseases. 2. The FOXP3 gene acts as the master transcription factor for the development of regulatory T cells. 3. Central immune tolerance occurs in the peripheral blood, whereas peripheral tolerance occurs in the thymus. How many of the above statements are correct?
Q2
Match the FollowingMatch the following terms related to the 2025 Nobel Prize in Medicine with their descriptions: List I: A. FOXP3, B. IPEX Syndrome, C. Central Tolerance, D. Scurfy mice. List II: 1. Elimination of self-reactive T cells in the thymus, 2. Animal model with a fatal autoimmune defect, 3. Human autoimmune disease caused by a specific gene mutation, 4. Transcription factor essential for Regulatory T cell development.
Q3
Assertion & ReasonAssertion (A): Mutations in the human FOXP3 gene lead to the severe autoimmune disorder known as IPEX syndrome. Reason (R): The FOXP3 gene encodes a transcription factor that programs T-cells to become Cytotoxic T-cells, which destroy self-tissues. Select the correct answer.