UPSC Prelims 2025 Q48: Monoclonal Antibodies and Nipah — Explained
With reference to monoclonal antibodies, often mentioned in news, consider the following statements:
I. They are man-made proteins.
II. They stimulate immunological function due to their ability to bind to specific antigens.
III. They are used in treating viral infections like that of Nipah virus.
Which of the statements given above are correct?
- I and II only
- II and III only
- I and III only
- I, II and III
Answer: (d) I, II and III
Statement-wise explanation
- I: correct — Monoclonal antibodies (mAbs) are proteins made in a laboratory. They copy the antibodies that the body's B cells make. The classic method fuses a single B cell with a myeloma (cancer) cell to make a 'hybridoma'. The hybridoma keeps producing one identical antibody, which is why they are called 'monoclonal'. Today most are made in engineered cell lines in bioreactors, so 'man-made proteins' is a fair description.
- II: correct — Each mAb is designed to bind one specific antigen, such as a viral surface protein or a receptor on a cancer cell. Once bound, it can neutralise a virus, mark a cell so that immune cells and complement destroy it, or block a signal. In this way it adds to and directs the body's own immune response. The exact way each mAb works varies, but binding to a specific antigen is what lets every one of them act on the immune system.
- III: correct — The human monoclonal antibody m102.4 targets the G glycoprotein of Hendra and Nipah viruses. India got doses through ICMR from the University of Queensland, Australia. It was used on a compassionate-use basis during the Kerala outbreaks of 2018, 2023 and 2024. It is not yet a licensed Nipah drug, but it is used to treat infection, so the statement holds. mAbs are also licensed for other viral infections, such as nirsevimab for RSV, and they were given emergency approval for COVID-19.
How to eliminate
Statements I and II are close to textbook definitions. A monoclonal antibody is a lab-made copy of an antibody, and its whole purpose is to bind one specific antigen. If you know only that much, you can rule out the one option that leaves out both I and II. Statement III is the current-affairs part. It has no absolute words like 'only' or 'always', and it says just that mAbs are used for viral infections such as Nipah. That was in the news because India imported an anti-Nipah mAb from Australia during the Kerala outbreaks of 2018, 2023 and 2024. To be sure, you need to remember that fact: ICMR obtained the m102.4 monoclonal antibody for Nipah patients in Kozhikode and Malappuram. When the statements are mild, definition-style claims about a well-known technology, UPSC often marks all of them correct.
Know more
Monoclonal antibodies (mAbs) are identical copies of one antibody. Each recognises one epitope, the specific part of an antigen it binds to.
How they are made
- In 1975 Georges Köhler and César Milstein fused antibody-making B cells with myeloma cells to make hybridomas. These cells live indefinitely and keep making the same antibody. The two shared the 1984 Nobel Prize.
- Early mAbs came from mice and could trigger immune reactions in patients. Newer ones are chimeric, humanised or fully human. The name tells you which:
| Suffix | Source | Example |
|---|---|---|
| -ximab | Chimeric (mouse + human) | Rituximab |
| -zumab | Humanised | Trastuzumab |
| -umab | Fully human | Adalimumab |
How they act
- Neutralisation: they block a virus from entering cells (anti-Nipah m102.4, anti-RSV nirsevimab).
- Tagging: they mark cancer cells for immune cells and complement to kill.
- Blocking signals: they shut down receptors or cytokines (anti-TNF drugs for arthritis; checkpoint inhibitors such as pembrolizumab, which take the brakes off T cells).
- Delivery: as antibody-drug conjugates, they carry a toxin straight to tumour cells.
Passive vs active immunity
| mAb therapy | Vaccine | |
|---|---|---|
| Immunity type | Passive (ready-made antibody) | Active (body makes its own) |
| Onset | Immediate | Weeks |
| Duration | Weeks to months | Long-lasting memory |
Nipah and mAbs in India Nipah is a zoonotic henipavirus. Fruit bats (Pteropus) carry it naturally. It has no licensed vaccine or drug. Kerala has had repeated outbreaks: 2018, 2019, 2021, 2023 and 2024. In each recent outbreak, ICMR supplied m102.4 for compassionate use. mAbs are biologics, so their copies are called biosimilars, not generics. India is building its own capacity to make them.
In the news
Kerala had Nipah outbreaks in Kozhikode (September 2023) and Malappuram (2024). Both times ICMR arranged monoclonal antibody doses from Australia, and this was widely reported. In the same period, mAbs were in the news for COVID-19, cancer and Alzheimer's treatment.