IISER Mohali team harnesses nanobodies that can neutralise all four strains of virus In a breakthrough that sounds like science fiction but is rooted in rigorous biological research, scientists at Indian Institute of Science Education and Research (IISER) Mohali have discovered a potential new weapon against dengue in an unlikely place: the immune system of the camel. Led by Dr Sharvan Sehrawat, the team has successfully harnessed nanobodies — miniature, ultra-tough versions of antibodies — to neutralise all four strains of the dengue virus. This discovery could come as a major relief for India, which currently accounts for nearly one-third of the global dengue burden (around 60 lakh infections annually). The study, published in Immuno Horizons, marks the first time such a technology has been developed in the country, offering a potential cure for a disease that strikes with regularity, particularly after rains. Dengue is a tricky disease. With most other diseases, a first infection leaves one immune. But with dengue, a second infection with a different strain can actually be more lethal. This is due to Antibody-Dependent Enhancement (ADE), which in simple terms means that the antibodies from the first infection can grab the new virus but can’t kill it. Instead, they inadvertently help the virus enter human cells more easily, leading to severe complications such as internal bleeding and shock syndrome. This ‘backfiring’ of the immune system has made vaccine development a global medical conundrum. 
Camels possess a unique biological quirk: they produce antibodies that can easily be formatted as ‘single-domain antibodies’ or nanobodies. Unlike human antibodies, which are large and complex, nanobodies are stripped down to their most essential viral-fighting components. Crucially, they lack the ‘Fc region’ — the specific part of a conventional antibody that is suspected of triggering the dangerous ADE effect. “Since these nanobodies are missing the piece that causes the disease to enhance, they are inherently safer,” explains Dr Sehrawat, associate professor at IISER Mohali. “They are smaller and tougher, and can reach parts of the virus that larger human antibodies simply cannot.”The research team didn’t just find one antibody, it built a massive ‘molecular library’ containing over 200 million antibody sequences derived from camel samples. By searching through this library, the team identified a specific nanobody that clings to the dengue virus’s ‘envelope protein’ — the key the virus uses to unlock human cells. By jamming this lock, the nanobody halts the infection in its tracks. In laboratory tests and animal trials, results astonished the researchers. Mice with lethal dengue infections showed total recovery. The treatment significantly lowered viral loads and prevented organ inflammation. Unlike current experimental treatments, no adverse reactions were recorded. The IISER team is now looking towards the next frontier, which is to explore ways for mass production. Instead of expensive, high-tech factories, it is turning to ‘molecular farming’. The researchers have successfully grown these antibodies inside lab plants like tobacco and Arabidopsis (small flowering plants in the cabbage and mustard family). However, the goal is to move production into common fruits like bananas. “Plants produce a lot of biomass quickly,” says Dr Sehrawat. “In future, we could potentially harvest these medicines from fruit, making the treatment much cheaper and accessible to the masses.” While the first-generation treatment is effective, it requires daily doses. The IISER team is now working on a ‘bivalent’ version that involves injecting a super-antibody into a dengue patient. This, according to the researchers, is a single-injection treatment. IISER has received approval from the Indian Council for Medical Research for a three-year project to upscale the therapy.
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