Analysis by I Know First correspondent Alan Moore
Please turn on JavaScript. Media requires JavaScript to play. Advertisement What a difference 100 years makes. Remember the first time you heard of (and probably hated) bacteria-based medicine? Purity has been key to medicine since the earliest time, when cures for anything from tuberculosis to yellow fever were created from human blood. An antibiotic called penicillin developed in the early 20th Century was specifically created and published as a bacterium from the day it was discovered. But now bacteria have taken over. Consisting of simple single cells, they now offer us a unique opportunity to test new drugs in the most natural and wide-ranging ways. They are also probably more versatile than humans. They’re flexible, self-replicating, mutable – and may even exist in extinction-threatened groups like Neanderthals. This appears to be changing the way in which treatments are developed. In a recent study, an international team of scientists demonstrated that the development of new drugs has always been dependent on its ability to survive in human beings. And the better a drug does this, the more it has kept evolving through the ages. Revolving door We know that given the basic properties of bacteria, they can easily function in the natural environment as we imagine it would. All we have to do is keep the thinking cap on
Professor Peter Foley
University of British Columbia for instance, in the late 90s, a natural killer cell (NK cell) from our own bodies appeared to be providing us with a new malaria drug that could kill the parasites that cause malaria. The only problem was that our cells were highly sensitive to a very strong natural killer activity that our own gene pushes out of us and would be a distraction as we killed parasites. In the same way, if a promising new antibiotic were to be specifically synthesised from a living organism, it was almost impossible to drive it through the natural selection into a drug that our cells would actually tolerate. CHANGING LANDSCAPE In 1995, a team of scientists observed that the destruction of anthrax spores in the lab could not be mimicked by antibodies made from any animal, so they ended up synthesising those antibodies in the lab instead. The results were straightforward. They found that the antibody was able to survive admixture with anthrax cells that had been exposed to a powerful antibody from the same organism, and within months, it had gone through the next evolution – to become an anti-anthrax antibody. Scientists believe the transition of the antibiotic to its current form is a normal part of evolution because it will favour the ability to become resistant. By taking the chimpanzee-based natural killer drug into the laboratory with them, we now know that the increased morphological complexity of the antibodies has sped up the process of evolution. In this way, researchers have shown how evolution is accelerating and identifying more targets for new drugs. Taking this a step further, the process may be helping us to discover how an antibiotic works and how to improve it. What we are doing now is actually developing new treatments in the laboratory, then replicating them and exposing them to other human cell lines. Ultimately, the laboratory may well be playing a much larger role than in the past. Bacteria-based medicine could replace our current need for as many as 12 different drugs used to fight illnesses in the developing world (including antibiotics used for malaria and HIV infection). The number could be even higher, especially in developing countries where people have limited access to doctors, as it is in the UK. Following extensive studies of the human body, human proteins can be successfully used to create the new medicines. Naturally occurring human genes are now commonly being used to develop these drugs. It is also possible for these new drugs to be tested in the lab to find out how well they work on human cells, instead of using animals that have to be kept alive in large cages. It is this computer-based biophysical simulation that helps focus our minds and arms race with bacteria. Doing so greatly increases the chances of solving some of the most difficult problems of life. Prof. Peter Foley is a biophysics professor and biomedical engineer at the University of British Columbia. Mr Moore’s report can be found here: www.ifoknowfirst.com
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