A synthetic antibody to detect krait venom
doi:10.1038/nindia.2019.2 Published online 10 January 2019
Researchers have created a synthetic molecule that can detect krait venom from as little as 2 nanogram (or ng, a billionth of a gram) of crude venom1.
Indian antivenoms are polyvalent: they consist of antibodies against the Indian cobra, the krait, the Russell’s viper and the saw-scaled viper. As there is currently no method to identify the snake behind the bite, large quantities of the polyvalent antivenom are often used, further increasing the risk of allergic reactions.
Also, the snake venom is a complex cocktail of chemicals that varies with geography, diet and age of the snake. This has made creating an antibody-based diagnostic test difficult.
In 2014, researchers from the University of Queensland created an aptamer, a synthetic antibody, to detect the venom of Bungarus multicinctus, the many-banded krait found in South-east Asia and islands in East Asia.
Indian researchers found that the venom against the common krait in India is 80 per cent similar to the venom of the many-banded krait. This led them to investigate whether this synthetic antibody could work to detect the venom of the common krait.
The researchers further trimmed the synthetic compound to achieve its smallest functional unit. They found that, when faced with the venom of eight different snakes, this trimmed compound could specifically detect common-krait venom from as low as 2 ng of crude venom. This showed that it is very specific and has low cross-reactivity to other venoms.
They also found that the aptamer could detect krait venom from three different locations in India: West Bengal, Maharashtra and Uttar Pradesh.
Such studies could lead to aptamer-based diagnostic kits for Indian krait bites.
1. Dhiman A et al. Rational truncation of aptamer for cross-species application to detect krait envenomation. Scientific Reports 8,17795 (2018) doi: 10.1038/s41598-018-35985-1