Monoclonal Antibodies

It is a protein made in a laboratory. It copies the work of a natural antibody.

What does “monoclonal” mean?

• “Mono” means one. “Clonal” means copies from one cell.
• All the antibody molecules in the drug are identical.
• They come from one parent immune cell.
• A natural immune response makes many different antibodies instead.
• Each monoclonal antibody fits one particular target, called an antigen.

What is the memory hook?

Think “one cell, one key, one lock”. One parent, identical copies, one target.

They find one target and stick to it. That action triggers a helpful effect.

What happens when one binds?

• The antibody binds its antigen like a key in a lock.
• Binding can block a harmful signal.
• Adalimumab is an example. It binds to TNF-alpha, a molecule that drives inflammation.
• Blocking TNF-alpha lowers the inflammation.
• This lets doctors aim a drug at one target in the body.

What is the memory hook?

Think “bind, block, calm”. Binding blocks the signal and calms the disease.

Early antibodies came from mouse cells. Scientists grew those cells in the lab.

What is a hybridoma?

• A hybridoma is a cell line that makes one kind of antibody.
• A few approved antibody drugs are made in hybridomas.
• Newer drugs are often made in other lab cell lines.

What was the first one?

• The first antibody drug on the market was muromonab-CD3, also called Orthoclone OKT3.
• The US FDA approved it in 1986.
• It helped stop T-cell rejection in kidney transplants.
• It was a mouse antibody, so the body saw it as foreign.
• After a few treatments, patients made antibodies against the mouse parts.

What is the memory hook?

Think “1986, mouse, kidney”. The first drug was a mouse antibody for transplants.

Scientists made the drugs more human to avoid the body’s reaction.

What are the four kinds?

• Murine antibodies are fully mouse. The body attacks them.
• Chimeric antibodies are about 70 percent human.
• Humanized antibodies are about 85 to 90 percent human.
• Fully human antibodies are entirely human.
• A more human antibody is less likely to trigger the immune system.

How do the names help?

• The WHO runs a naming scheme for these drugs.
• Every name ends in “-mab”.
• The letters before it show the origin: “-xi-” for chimeric and “-zu-” for humanized.
• Rituximab is chimeric. Its “-xi-” tells you so.

What is the memory hook?

Think “xi for mix, zu for zoom to human”. Each step is more human.

They treat many diseases because each drug can aim at its own target.

What are some examples?

• Rituximab is aimed at a tumour target.
• Adalimumab treats inflammation by blocking TNF-alpha.
• New antibody drugs are approved in Europe and the United States on a regular basis.
• Trastuzumab (Herceptin) is one drug on the PMC review’s approved list.
• Antibodies are also used against viral infections such as Nipah virus, as UPSC’s 2025 key confirms.

What is the memory hook?

Think “one drug, one target”. The target decides the disease.

India has used a Nipah antibody as an emergency treatment. There is no Nipah vaccine yet.

What is m102.4?

• m102.4 is a human monoclonal antibody against Nipah virus.
• Dr Christopher Broder developed it.
• It was still known by a number because clinical trials were not finished.
• It is an antibody, not a vaccine.
• It neutralised the virus in laboratory tests.

How did it reach India?

• Kerala had its first Nipah outbreak in May 2018.
• The antibody came from the University of Queensland in Australia.
• ICMR arranged the transfer.
• In 2023 the ICMR chief said India had asked for 20 more doses.
• Patients in early infection were given monoclonal antibody doses.

What is the memory hook?

Think “Nipah, Kerala, m102.4”. A number stood in for a name.

UPSC asked about monoclonal antibodies in 2025.

What was the question?

The key is option (d). All three statements are correct. View the UPSC CSP 2025 paper.

What are the traps?

• Antibody or vaccine? m102.4 is an antibody. A vaccine trains your own body.
• Natural or made? The drug is man-made, not taken from a person.
• Which name? “-xi-” is chimeric and “-zu-” is humanized.

What is the memory hook?

Think “man-made, binds, Nipah”. All three statements were true.