May 10, 2013
Synthetic Spider Toxin Defend Against Multiple Venom Types
April Flowers for redOrbit.com - Your Universe Online
Scientists say they have engineered a spider protein that could be the start of a new generation of anti-venom vaccines, with the potential to save thousands of lives worldwide. Researchers from the Universidade Federal de minas Gerais in Brazil say the new protein, created from parts of the toxin from the reaper spider, may be a promising candidate for developing therapeutic serums or vaccines against other venoms.
Part of a family of spiders called Loxoscelidae that can be found all over the globe, reaper spiders — also known as brown spiders — produce harmful venoms that cause the skin around the bite to die. The bites can also lead to more serious effects like kidney failure and hemorrhaging. Almost 7,000 human accidents a year are caused in Brazil where these Loxosceles spiders are most prevalent.
The new study was published in the journal Vaccine and describes an engineered protein made of three pieces of a venom toxin from the species Loxosceles intermedia. The synthetic protein is not toxic, but it does provide effective protection against the effects of the pure organic spider venom in animal models.
"In Brazil we see thousands of cases of people being bitten by“¯Loxosceles“¯spiders, and the bites can have very serious side-effects," said Dr. ChÃ¡vez-Olortegui. "Existing anti-venoms are made of the pure toxins and can be harmful to people who take them. We wanted to develop a new way of protecting people from the effects of these spider bites, without having to suffer from side-effects."
Current approaches for creating treatments for venom involve giving the venom to animals, then extracting the antibodies that the subject produces to create the serum. The antibodies prepare the human immune system to neutralize venom from bites. The production of anti-venoms such as these is problematic, although somewhat effective. Animals are required to produce these antibodies and they suffer from the effects of the venom.
The new protein, however, is laboratory engineered without the need to harm animals. Additionally, the synthetic protein is made from three proteins, so it can protect against more than one kind of toxin at a time, and it is not harmful to the immunized animal that produces the antibodies. The new protein is also more effective and easier to produce than the serums created from organic spider venom.
"It's not easy taking venom from a spider, a snake or any other kind of venomous animal," said ChÃ¡vez-Olortegui. "With our new method, we would be able to engineer the proteins in the lab without having to isolate whole toxins from venom. This makes the whole process much safer."
The new protein was tested on rabbits in the lab. All immunized animals showed an immune response similar to the way they respond to the whole toxin. The research team found that the protein was effective for the venom of “¯the“¯L. intermedia and“¯L. gaucho sub-species, which have similar toxins. The immunized rabbits were protected from both skin damage at the injection site and hemorrhaging.
The scientists also believe the new protein might be a promising candidate for therapeutic serum development or future vaccinations.