Kanpur: Scientists at IIT Kanpur have revealed how an experimental molecule called EP67 switches on an important receptor found on human immune cells. EP67 is a candidate ‘adjuvant’, an ingredient added to vaccines to make them work better.
The finding, published in the journal Proceedings of the National Academy of Sciences (PNAS), gives researchers the first clear, close-up view of EP67 gripping its target, and hands them a blueprint for designing safer vaccines and new immune-based treatments.
When one catch a bacterial or viral infection, our immune cells release a small protein called C5a, which primes the immune system to fight back. But too much of C5a for too long leads to inflammation that is harmful and can damage healthy tissue. To prevent this, the body uses enzymes in the blood to break C5a down quickly once the threat has passed.
The researchers at IIT Kanpur took a cue from this natural safety mechanism and built a stripped-down copy of C5a, a short chain of just ten amino acids named EP67, that keeps the useful part of C5a’s activity but works in a gentler way.
This is exactly what is needed in a vaccine booster – a stronger, longer-lasting immune response without the collateral damage.
Earlier animal studies support this – when EP67 was added to vaccines against several viruses in mice, including the virus that causes COVID-19, the animals mounted a stronger immune response than with the vaccine alone and also tended to recover faster. EP67 has also shown a surprising ability to fight bacterial infections.
The study led by the laboratory of Professor Arun K. Shukla in the Department of Biological Sciences and Bioengineering at IIT Kanpur was published in PNAS in July 2026.
The research was supported by the Indian Council of Medical Research (ICMR), the Anusandhan National Research Foundation (ANRF), the Department of Biotechnology (DBT), and the Department of Science and Technology (DST). The high-resolution structure was determined at the National cryo-EM Facility at IIT Kanpur, set up with funding from ANRF.
