BEIJING, Feb. 22 (Xinhua) -- A TEAM OF AMERICAN RESEARCHERS SAID IN A NEW ISSUE OF THE JOURNAL SCIENCE TRANSLATIONAL MEDICINE THAT THEY HAVE FOUND AN ANTIBODY THAT CAN FIGHT THE DEADLY VENOM OF A VARIETY OF VENOMOUS SNAKES. This represents a big step towards the development of broad-spectrum antivenoms.
According to statistics, more than 100,000 people die from poisoning after snake bites worldwide every year. The antivenom currently used in clinical practice is prepared after immunization of large mammals with snake venom. For example, if a horse is injected with a low dose of snake venom, the horse's serum will contain anti-venom antibodies after a period of time. However, because the venom composition of different species of venomous snakes varies, usually one antivenom can only fight the corresponding single snake venom.
The Scripps Research Institute team that conducted the study said that antibodies that bind to one snake venom usually do not bind to other snake venoms due to variation between different snake venoms, but they realized that snake toxins also have "conserved" regions that do not mutate, and antibodies targeting these regions may fight against all variants of the toxin.
To develop antibodies against a variety of snake venoms, researchers isolated and compared the venoms of several cobras and found that a venom protein belonging to the "three finger toxins" (a class of neurotoxin) is present in the venom of all species of cobras. In the venom of different species of cobras, the protein all contains specific small areas that look similar. Therefore, the researchers believe that this protein is an ideal target for antivenom.
Using the gene that encodes the "three-finger toxin" protein, the researchers made the toxin in the lab and searched for the corresponding antibodies in a huge library of human antibodies. Eventually, they screened out an antibody called 95mat5, which can strongly bind to different variants of the "three-finger toxin" protein, blocking the "three-finger toxin" from exerting neurotoxicity and thus acting as an anti-toxic effect.
In current animal experiments, this antibody has successfully protected laboratory rats from the venom of many venomous snakes such as cobras, ring snakes, and black mamba snakes. The laboratory rats were injected with different snake venom and did not become paralyzed or die.
Researchers hope to further develop broad-spectrum antivenoms that can fight a wide range of snake venoms. Especially in low- and middle-income countries, broad-spectrum antibody treatment can not only save a lot of lives, but also greatly reduce the medical burden of the injured.