By Stephen Beech via SWNS
A better way of treating potentially deadly black widow spider bites with fewer side effects has been developed.
Human antibodies have been engineered by scientists to neutralise the arachnid’s toxin.
The breakthrough potentially reduces the need for antibodies derived from horses to treat diseases caused by spider bites.
There are several types of widow spiders, including black, red, and brown varieties in North and South America, the Australian redback spider, and several button spider species that inhabit South Africa.
In Europe, Latrodectus tredecimguttatus – the European black widow – inhabits the Mediterranean region.
But they have been expanding their habitat in recent times due to climate change, say scientists.
They explained that Widow spiders’ bites can cause latrodectism, a disease where the spider’s venom – a neurotoxin known as alpha-latrotoxin – attacks the nervous system and causes symptoms including severe pain, high blood pressure, headache, and nausea.
Black widow bites can be treated with antibodies derived from horses, but to make treatment safer for patients, researchers in Germany set out to develop fully human antibodies.
Study senior author Professor Michael Hust, a biologist at the Technical University of Braunschweig, said: “For the first time, we present human antibodies which show neutralization of black widow spider venom in a cell-based assay.
“This is the first step to replace the horse sera that are still used to treat the severe symptoms after a black widow spider bite.”
He says many patients bitten by black widows aren’t treated altogether because the antivenom is made from proteins derived from horses which are foreign to the human body and can cause “undesirable” side effects.
These include serum sickness, a reaction to proteins in antisera derived from non-human animal sources, and serious allergic reaction.
Hust says the available antivenom is also an undefined mix of antibodies that varies from batch to batch.
But, despite the shortcomings, that antivenom is the most efficient treatment option currently available.
Hust said: “We set out to replace horse sera with recombinant human antibodies to get a better product for the patients and to avoid the use of horses for serum production.”
To do so, the research team used an in vitro method called antibody phage display.
Hust said: “This approach uses extremely diverse gene collections of more than 10 billion different antibodies.
“From this large diversity of antibodies, phage display can fish out antibodies which can bind the desired target, in this case, the toxin.”
He says antibodies engineered in such a way can be repeatedly reproduced in the same quality because the DNA sequence of the human antibody is already known.
They also could improve animal welfare because horses do not need to be immunized and bleed to produce black window anti-toxins, says the research team.
Hust’s team came up with are antibody candidates that can be used for the development of therapeutic antibodies.
A total of 45 of 75 generated antibodies showed in-vitro neutralization of alpha-latrotoxin.
One antibody, called MRU44-4-A1, showed “outstandingly” high neutralization, according to the findings published in the journal Frontiers in Immunology.
But what surprised the research team was that just two of the antibodies turned out to be effective against the venom of other widow varieties.
Hust said: “To develop a potential treatment for all latrotoxins, and not only the toxin of the European black widow, we would need further improved cross-reactive antibodies.”
The researchers say further preclinical steps are needed to evaluate the efficacy of the antibodies before clinical trials can be started.
Hust added: “In another project, we have shown that we can develop human antibodies to treat diphtheria which are effective in in vivo studies.
“We intend to take the same steps for the black widow antivenom antibodies.
“This is especially important because, with the invasion of the spiders into new habitats, the incidence of latrodectism and the need for therapeutic alternatives might increase over the next years.”
