Nobel Prize in Physiology or Medicine 2025

Syllabus: GS3/Science and Technology

Context

• The Nobel Prize in medicine or physiology was announced for three scientists, for their discoveries on peripheral immune tolerance.
• The three scientists Mary Brunkow, Fred Ramsdell and Shimon Sakaguchi shared the Nobel Prize in Physiology or Medicine. 

Human Immune System

• The immune system protects the body from pathogens such as bacteria, viruses, fungi, and parasites.
  • It consists of organs, cells, and molecules that work together to recognize and eliminate harmful substances.
• Major Components of the Immune System: 
  • Organs: Bone marrow, thymus, spleen, lymph nodes, tonsils.
  • Cells: White blood cells (leukocytes) — lymphocytes, macrophages, neutrophils, etc.
  • Molecules: Antibodies, cytokines, complement proteins.
• These have a role in identifying and eliminating foreign bodies that may bring with it disease.
  • However the immune system also identifies cells that have gone rogue – such as in cancerous tumours – or that have mutated in a way that they harm the bodies they constitute. 
  • Telling apart benign cells from harmful invaders is the key challenge the immune system must negotiate.

What are B and T-Cells?

• B-cells and T-cells are a specific type of white blood cell called lymphocytes.
• They help the immune system to fight germs and protect from disease. 
• Types of T cells:
  • Cytotoxic T-cells: They kill cells infected with viruses and bacteria, and they also destroy tumor cells.
  • Helper T-cells: They send signals that direct other immune cells to fight infection.
  • Regulatory T-cells (Tregs): These cells suppress excessive immune responses to prevent autoimmune reactions and maintain immune tolerance.
    • They play a crucial role in preventing the immune system from attacking the body’s own cells and tissues.
• T-cells start in bone marrow, mature in thymus and eventually relocate to lymph tissue or bloodstream.
• B-cells make antibodies in response to antigens (antibody generators).
  • There are two main types of B-cells: plasma cells and memory cells. Both types help to protect from infection and disease.

Discovery

• The laureates identified the immune system’s security guards, regulatory T cells, which prevent immune cells from attacking our own body.

• Their discoveries have been decisive for our understanding of how the immune system functions and why we do not all develop serious autoimmune diseases.

Significance

• The laureates’ discoveries launched the field of peripheral tolerance, spurring the development of medical treatments for cancer and autoimmune diseases. 
• Once the function of these new T-cells were known, researchers realised that some tumours can attract a large number of these regulatory T cells, thereby protecting it from the other T cells.
• The discovery of Regulatory T-cells revolutionized immunology by revealing that the immune system is not only attack-oriented but also self-regulating.
• It has major implications for treating autoimmunity, cancer, transplantation, and chronic inflammation.

Source: TH