So it isn't ok here to use animal cells but it is ok in Vaccinations?
 

Alarms raised on pig-organ transplants
Advances for human use made; virus risk -- as in AIDS -- noted

Friday, January 4, 2002

By PAUL RECER
THE ASSOCIATED PRESS

WASHINGTON -- As science moves closer to using pig organs for human transplants, some experts caution that the technique could transfer deadly swine viruses, citing the example of the virus that causes AIDS. Ethicists question the idea of using animals to make spare parts for people. Two research teams announced this week that they have cloned piglets that lack one of two genes that prompt the human immune system to reject swine tissue. The next step is breeding or cloning that would eliminate the gene from a strain of pigs.

In a world where more than 5,700 people in need of transplants die each year because of the shortage of donated organs, many researchers view pigs as a potentially unlimited supply source. But some experts caution that the whole field of xenotransplantation -- transplanting tissue from one species to another -- is fraught with infection risks, both to the transplant recipients and, perhaps, to other humans as well.

Pigs are known to contain what are called porcine endogenous retroviruses or PERVs -- viruses that evolved with the swine over millions of years and now are part of the animals' genes. The viruses do not affect the pig, but what would happen if the animal's organs are transplanted into humans? Perhaps nothing, or perhaps it could lead to a whole new disease, say some experts. "This is a recipe for disaster," Alix Fano, head of the Campaign for Responsible Transplantation, an organization of scientists and doctors opposed to xenotransplantation. "Pigs are a reservoir of viruses and we have no idea what their organs would do if transferred to humans."

Others agree that swine viruses are a serious, complex problem with no clear solution now, but they believe science will find a way. "That is a genuine concern. There is a risk," said George Agich, chairman of bioethics at the Cleveland Clinic. "The ethical question is whether there is a risk to the general population from a procedure that would benefit a single individual. But we have at our disposal scientific means to determine if that risk is reasonable." Until then, he said, "we should be extremely cautious. We may be talking about decades before we can roll out this technology (xenotransplantation)."

Some studies in which humans were exposed to pig cells have suggested that PERVs do not infect human cells. But critics say there are many other examples showing that some retroviruses that are harmless in one species become virulent killers when transplanted into humans. The most notable example, said Jonathan Allan of the Southwest Foundation for Biomedical Research, is HIV, the virus that causes AIDS. The retrovirus is thought, by some, to have lived harmlessly in the green monkey and became deadly only when it jumped to humans.

Allan said studies have shown that a virus that was a harmless part of the genes of the langur monkey became a serious pathogen when it infected the Rhesus monkey. Before pigs can be considered for the source of human organs, he said, much research will be needed to develop a level of confidence that the viral risk has been settled.

Dr. Randall Prather of the University of Missouri, a member of one of the teams that cloned the genetically altered piglets, said the problems can be addressed, but only if pigs are developed whose organs would not be
rejected by the human immune system. Prather is co-author of the study appearing today in the journal Science.

Science: www.scienceexpress.org

Xenotransplantation: www.transplant.ca/xeno.htm
 

http://www.cnn.com/2003/HEALTH/12/13/sprj.flu03.vaccine/index.html

(CNN) -- Members of an advisory panel that backed this year's flu vaccine expressed doubts about its potential effectiveness before recommending it for the Food and Drug Administration's approval.

Some said they were concerned the vaccine would not provide as much protection against the Fujian strain of flu that was thought most likely to dominate this year's flu season, according to a transcript of the group's deliberations.

The Fujian strain, which emerged in the Far East, is now responsible for 75 percent of U.S. flu cases, the Centers for Disease Control and Prevention said. But drug makers could not culture the Fujian strain in a way to meet FDA standards, forcing the advisory committee to make this year's flu vaccine the same as it was last year.

The committee's decision in March has come under a microscope now because the flu is reaching near epidemic proportions in the United States. Dr. Theodore Eickhoff, a professor of infectious diseases at the University of Colorado Health Sciences Center in Denver, said he was voting reluctantly to recommend the current vaccine, according to the transcript.

"For the first time in many years of participating in these deliberations, I must add that I am very uncomfortable with that recommendation," Eickhoff said. The final vote in a March 18 meeting was 17 in favor of the current vaccine, two abstentions and one opposed. The FDA later approved the vaccine.

Dr. Peter Palese, chief of microbiology at New York's Mount Sinai Hospital, was the sole member to vote against the recommendation of the Vaccine and Related Biological Products Advisory Committee. A number of people said they felt they were given no choice, according to the transcript.

"I would prefer that we move to an A/Fujian-like strain," said Dr. Pam Diaz of the Chicago, Illinois, Department of Public Health. "However, it seems from a regulatory standpoint, in terms of manufacturing, that we  have our hands tied." Nancy Cox, chief of the influenza branch at the CDC, told the group that  manufacturers had been unable to grow the Fujian strain in chicken eggs -- the only FDA-approved method of reproducing the virus for use in vaccines. "It's just not working this time," she said. "We don't know why." But, she added, when lab workers extracted the Fujian strain from dog kidneys and then put it into chicken eggs, it grew well.

The prospect of using a virus extracted from an animal did not sit well with Dr. Karen Midthun, director of the FDA's office of vaccines research and review, who said it could pose a risk to vaccine recipients  if it turned out to be contaminated. "One really needs to know a lot about the cells that were used," she said. "They need to be qualified, characterized, to really address the different safety issues that we feel need to be addressed." Palese disagreed, according to the transcript.

"One can make a reasonable argument" that there is a theoretical possibility that cells used in the approved vaccine could contain contaminants "and that we are perfectly happy to accept that," he said. "We are ... not making the best vaccine decision if we don't allow the Fujian type to be part of this new formulation." Palese downplayed the possibility of contamination, calling it "a potential very, very minimal risk."

He added, "If we have the technological abilities to make better vaccines, then we should make them, rather than sticking to old regulatory rules." Reached by telephone Saturday at Mount Sinai Hospital, Palese said, "I would rather not comment." Another member of the advisory panel, Dr. Samuel Katz, a virologist and infectious disease expert at Duke University Medical Center, was less reticent about Palese's lone vote in favor of adding the Fujian strain to this year's vaccine.

"Dr. Palese is the member of that committee most knowledgeable about influenza viruses," Katz told CNN in a phone interview from his home in Durham, North Carolina. "He was the only one there with the knowledge about reassortment and recombination of influenza viruses to say that he felt that there should  be some way to do that." Nearing epidemic proportions in U.S. The onset of this year's flu outbreak -- in October -- is earlier than in most seasons. Flu is widespread in 24 states, and cases have been reported in all 50  states.

Last week, pneumonia and influenza were blamed for 7 percent of all deaths logged by the country's reporting system that includes 122 cities, just below the 7.6 percent that the CDC said would represent the epidemic threshold. Only 25 percent of influenza viruses found so far are the Panama strain of Influenza A, which is contained in the current vaccine, according to the CDC. Though studies have shown that the Panama strain will have some effect against the Fujian strain, reports quantifying that effectiveness will  not be complete until after the flu season is over, the CDC said. Dr. Michael A. Decker of Aventis Pasteur, one of two U.S.-based  influenza vaccine manufacturers, said he would have included the Fujian strain if it were practical to do so.

"But it's also clear to me that trying to do so is likely to cause more  problems than it will help," Decker said. Given the problems in reproducing the virus, attempts to include it  could have delayed production of the vaccine, which is a four-month process. It could have meant that supplies would not have been available on time, the industry representative said. "The perfect vaccine, arriving in insufficient quantities and late, will  protect fewer people than the less perfect vaccine arriving abundantly and on time," he said.

(comforting huh.....)

Now scientists create a sheep that's 15% human

By CLAUDIA JOSEPH -  Last updated at 21:26pm on 24th March 2007

Scientists have created the world's first human-sheep chimera - which has the body of a sheep and half-human organs. The sheep have 15 per cent human cells and 85 per cent animal cells - and their evolution brings the prospect of animal organs being transplanted into humans one step closer. Professor Esmail Zanjani, of the University of Nevada, has spent seven years and £5million perfecting the technique, which involves injecting adult human cells into a sheep's foetus.

Chimera: sheep have 15 per cent human cells and 85 per cent animal cells

He has already created a sheep liver which has a large proportion of human cells and eventually hopes to precisely match a sheep to a transplant patient, using their own stem cells to create their own flock of sheep.

The process would involve extracting stem cells from the donor's bone marrow and injecting them into the peritoneum of a sheep's foetus. When the lamb is born, two months later, it would have a liver, heart, lungs and brain that are partly human and available for transplant.

"We would take a couple of ounces of bone marrow cells from the patient,' said Prof Zanjani, whose work is highlighted in a Channel 4 programme tomorrow.

"We would isolate the stem cells from them, inject them into the peritoneum of these animals and then these cells would get distributed throughout the metabolic system into the circulatory system of all the organs in the body. The two ounces of stem cell or bone marrow cell we get would provide enough stem cells to do about ten foetuses. So you don't just have one organ for transplant purposes, you have many available in case the first one fails."

At present 7,168 patients are waiting for an organ transplant in Britain alone, and two thirds of them are expected to die before an organ becomes available.

Scientists at King's College, London, and the North East Stem Cell Institute in Newcastle have now applied to the HFEA, the Government's fertility watchdog, for permission to start work on the chimeras.

But the development is likely to revive criticisms about scientists playing God, with the possibility of silent viruses, which are harmless in animals, being introduced into the human race.

Dr Patrick Dixon, an international lecturer on biological trends, warned: "Many silent viruses could create a biological nightmare in humans. Mutant animal viruses are a real threat, as we have seen with HIV."

Animal rights activists fear that if the cells get mixed together, they could end up with cellular fusion, creating a hybrid which would have the features and characteristics of both man and sheep. But Prof Zanjani said: "Transplanting the cells into foetal sheep at this early stage does not result in fusion at all."

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