Researchers develop recombinant nanobody antivenom effective against Indian cobras

Every year in India, snakes kill nearly 50,000 people—more than any other country on earth. The bites come without warning: a step in tall grass, a hand reaching into a dark corner, a moment of inattention. What follows is a race against toxins that attack the nervous system, the blood, the tissues themselves. For over a century, the only answer has been antivenom, a treatment that hasn't fundamentally changed since it was first developed.

The problem runs deeper than just the scale of deaths. Each snake species manufactures its own distinct cocktail of poisons. A spectacled cobra's venom works differently from a monocled cobra's, which differs again from a king cobra's. Current antivenoms, derived from animal blood—horses are immunized with venom, their antibodies harvested and bottled—struggle with this diversity. They vary from batch to batch. They carry side effects. They don't cover enough species. And they're expensive to produce, requiring the repeated, labor-intensive process of milking venom from living snakes and injecting it into animals to trigger an immune response.

In 2026, researchers at India's Institute of Science and the Technical University of Denmark announced a different approach. Kartik Sunagar, an associate professor at the Centre for Ecological Sciences, and Andreas Laustsen, a professor at DTU, had engineered a recombinant antivenom built from nanobodies—tiny antibody fragments, just the tip of the Y-shaped protein that does the actual binding work. The team published their findings in Science Translational Medicine.

The method borrowed from earlier work on African snakes. Laustsen's group had immunized camelids—alpacas and llamas—with venom from various African species, extracted the antibodies those animals produced, and then used microbial cells to mass-produce those antibodies in a laboratory. They displayed the antibodies on bacteriophages, exposed them to venom, and isolated the fragments that could neutralize the toxins. For the Indian cobra work, Sunagar and Laustsen's teams took those same camelid antibodies and exposed them to venom from Indian cobra species. The antibodies worked. They could bind to and neutralize the toxins these snakes produced.

The researchers isolated five nanobody fragments that together formed a cocktail capable of attacking toxins across multiple cobra species. In mice injected with venom from spectacled cobras, monocled cobras, and both Indian king cobra species, the nanobody cocktail protected the animals from death. Remarkably, even mice that had already become paralyzed—showing the full neurotoxic symptoms of envenomation—recovered to a completely normal state. The treatment worked even when administered 30 minutes after the venom injection, a critical window for human medicine.

What made this approach genuinely different was efficiency. Previous research required relatively large doses of monoclonal antibodies to neutralize snake venom in animal models. Sunagar's team demonstrated that carefully selected and engineered nanobodies could do the job with far smaller quantities. This matters because it addresses two persistent problems with current antivenoms: cost and safety concerns tied to administering large volumes of antibodies into a human body.

The recombinant approach also eliminates the need for repeated animal immunization. Microbial and humanized expression systems can manufacture these antibodies in controlled laboratory settings. Additional antibody components can be added to expand protection to other medically important snakes. A single platform could be adapted for different regions of the world, tailored to the specific snake species and toxin families that pose the greatest threat in each area. For India, where snakebite remains a neglected tropical disease claiming tens of thousands of lives annually, this represents the first genuinely new direction in antivenom development in over a century.