<p><b>Tobacco that brings health</b></p> <p>Viral tobacco mosaic is one of the oldest famous plant diseases. Plague, known in medieval Europe as "black death" is one of the oldest diseases that leads to mass death of people. For the last years plague has attracted attention because of its potential application as biological weapon. Recently, scientists were able to achieve changes of tobacco mosaic virus, thanks to which plants infected with it produced protein immune bodies against plague. It transformed tobacco greenhouses into biological plants of anti-plague vaccine.</p> <p>To make genetic modifications, specialists in biotechnology sphere Charles Arntzen and his colleagues from Arizona State University have used methodology that was worked out in Germany. First, they have introduced in tobacco plants tobacco mosaic virus modified in such a way that plants would produce one of three established earlier plague antigens - proteins that received name F1, V and their combination. Changed virus has reproduced quickly, filling plant's cells. But infected cells began to produce one of these three antigens. During ten days researchers have received harvest of tobacco leafs that can serve as vaccine against the plague. "Each time when replication takes place we get proteins that we need", - Arntzen says. Then researchers dispense leafs, getting approximately 2 mg of antigen on each gram of leafs and clear vaccine with acids. Scientists from U.S. Army Medical Research Institute of Infectious Disease, Maryland, have vaccinated eight female of guinea pig with different variants of antigens and than have exposed them Yersinia pestis bacterial contamination that provokes pneumonic plague that is air-communicable. This form of plague gives the most quantity of fatal cases. During six days all pigs unvaccinated against the plague from control group have died. From vaccinated survived 60% of animals, but those, who died lived more than six days. The most effective appeared to be antigen V that saved 75% of vaccinated animals.</p> <p>Now, came time of clinical experiments. If vaccine aces it will be able to provide reliable protection against strains that became resistive as regards to famous antibiotics that where effective remedy some time ago.</p>