A novel biological weapon/vaccine developed through genetic engineering
by Tamara Traubman
In the picture: the anthrax bacterium. Today there are two types of unsuccessful vaccines
Scientists from the Biological Institute in Ness Ziona recently conducted experiments with a vaccine against the anthrax bacteria, intended for use in biological warfare. Experts hope that the vaccine, developed using genetic engineering methods, will be able to provide protection against the deadly bacteria in the future. Experts previously estimated that the dispersion of the anthrax over the city of Washington, for example, could kill about three million people. According to foreign publications, there are several countries developing biological weapons, including Israel. Iraq and Syria are also known.
The public is rarely exposed to what is happening at the Biological Institute in Nes Ziona, even when it comes to projects of a non-military nature. Some of the information about the action of the vaccine developed in Israel and how it was developed were recently published in "Infection and Immunity", a scientific journal published by the American Society for Microbiology. The research is headed by Dr. Avigdor Shaferman, director of the biological institute.
There are two approved types of anthrax vaccine today, and experts agree that these are not good enough. "The protective effectiveness of vaccines is less than ideal," wrote Dr. Peter Turnbull, a British anthrax expert, in 1991. One of the vaccines, developed in the USA and given to soldiers in the American army, was approved for use in 1970, and since then its composition has not changed. The second vaccine is used by the Russian army, and is based on a weakened version of the bacteria. The Russian vaccine is slightly more effective than the American one, but its use involves many side effects.
Discontent with existing vaccines grew in 1998, after it was discovered that Russia had a new type of anthrax. The information was discovered after scientists from the Los Alamos National Laboratory in the USA examined tissues of those killed in an accident that occurred in 1979 at a Soviet military site in Sverdlovsk. As a result of that accident, anthrax bacteria were released into the air. In another, more recent test - done years later and using modern methods - the US discovered that Russia had mixed together several strains of anthrax. It has been hypothesized that this was done to increase the degree of lethality of the bacteria, and that the American vaccine may not be effective enough against the new type.
In the last four years, scientific publications have come out calling for the development of a new vaccine, but the great risk involved in working with anthrax, and the cost of establishing a laboratory to treat dangerous bacteria, meant that only a few laboratories in the world are working on the development of such a vaccine.
In developing the vaccine, Dr. Shefferman and his colleagues used a non-violent strain of anthrax. With the help of genetic engineering, they implanted in a bacterium a gene responsible for the production of an antigen, which is a non-toxic molecule that stimulates the body to produce antibodies that fight the bacterium. The researchers call the resulting transgenic strain MASC-10. Since genes are usually not active all the time, the researchers added a biological controller that causes the gene to be constantly active and constantly maintain large amounts of antigen. Thus, the researchers hope, the vaccine will provide permanent protection over time.
"The vaccine is conceptually different from the others," agrees Dr. Alon Mozes, an infectious disease expert and researcher at the Hebrew University School of Medicine and Hadassah Hospital. "But", he adds, "since they used a weakened cell of the bacterium, the question of side effects remains open. Once you inject a whole cell, even an attenuated one, there can be all kinds of general side effects, like heat or swelling at the injection site. These are not necessarily serious side effects, but they are unpleasant."
The Mans Ziona researchers will encounter difficulty when they try to examine the side effects and effectiveness of the vaccine in humans. This is because such a test obviously involves exposing humans to bacteria, an experiment that does not meet the rules of ethics.
So far, the vaccine has only been tested in eight guinea pigs, but the results are encouraging. The guinea pigs that did not receive the vaccine died within about three days. In contrast, all the guinea pigs that received the vaccine survived. The effect of the vaccine did not wear off during the 12 months that have passed since the trial began.
If the vaccine turns out to be effective in subsequent trials as well, it will have at least one clear advantage over the American one. The American vaccine involves six doses that are injected separately. The Mans Ziona vaccine, at least in guinea pigs, provides protection even with a single injection.
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