Aftermath of an Experiment
DURING THE ANTHRAX EVENT,
Lisa Hensley kept her head down and worked on her smallpox data. Nobody from the FBI called her or gave her a polygraph exam, and she felt oddly disappointed about that. She was not involved with the anthrax investigation at
USAMRIID.
Meanwhile, the scientific community had begun to hear rumors that Peter Jahrling and his team had re-created smallpox in monkeys and that Jahrling had plans to write a paper about it. D. A. Henderson, who was now working inside the U.S. government, was clearly not happy about this monkey work, but he couldn’t speak out in public because the official policy of the government was to develop alternatives to the traditional vaccine.
Henderson felt that a stockpile of the traditional vaccine would be more than adequate. He worked with officials from the CDC to develop a national plan for a smallpox emergency. The CDC would give ring vaccinations to the affected populations, and if those failed, everyone who could tolerate the vaccine would get it. At the same time, the U.S. Public Health Service (the parent of the CDC) would institute quarantines around cities. The National Guard would most likely have to be involved, and so the plan had elements of martial law.
WHEN HENDERSON
had retired as the dean of the Johns Hopkins School of Public Health, he was replaced by an epidemiologist, Dr. Alfred Sommer, who had worked in the CDC’s Epidemic Intelligence Service during the years of the Eradication. In 1970, when the cyclone hit Bhola Island, which would inspire Larry Brilliant and Wavy Gravy to go there to try to help, Al Sommer was already there. He happened to be stationed in Bangladesh with the CDC, and he ended up organizing help in an area of jungle islands in the Ganges Delta known as the Sunderbunds, not far from Bhola Island. He pioneered some of the first techniques of disaster-assessment epidemiology, methods that are now used everywhere to monitor diseases in populations that have been hit with a natural disaster.
Not long afterward, Bangladesh won its independence from Pakistan. During the civil war, ten million refugees ended up living in camps just inside India, where smallpox broke out. Sommer fought smallpox for two months in the refugee camps, often the only medical doctor at the scene. “It was just me and a couple thousand cases of smallpox, which meant five hundred to eight hundred deaths,” he said. He discovered that local cemeteries were a good place to trace the movement of the virus. “People buried their dead in Bangladesh rather than cremating them, as they do in India,” he said, “and they always knew when a person died of smallpox.” He studied the registries of burials, and he could see the rising and falling of the generations of the virus. He used this information to determine where to set up a ring, where to vaccinate people. Today, Sommer keeps a certificate from the WHO on the wall of his office, noting his participation in the Eradication. He is as proud of it as of his Lasker Award, which is the most prestigious award in medicine. He received the Lasker for research in vitamin A deficiencies and blindness.
One day in January 2002, Sommer was having lunch at the Hamilton Street Club in Baltimore, which is frequented by journalists and literary types. An editor from the Baltimore
Sun
showed him a front-page article from the day before, about Peter Jahrling and his work with smallpox at the CDC, and said, “The U
SAMRIID
people are killing monkeys with smallpox, and they’re proud of it. What do you think of that, Al?”
Sommer said that his reaction was, “Excuse me? They’re
what
?” He stared at the newspaper and couldn’t believe what he was reading. “I started to vibrate at the visceral level,” he said. “We could have eradicated smallpox completely if we had just destroyed the stocks a couple of years after the Eradication. And now there was Peter Jahrling exulting in the fact that he could kill these monkeys with smallpox. I went bananas.” Sommer was leaving on a trip to Thailand the next morning, but he whipped off an op-ed piece for the paper.
It began: “One needn’t be a Luddite to recognize an idiot—and the government scientists gloating . . . over their ability to infect monkeys with smallpox are idiots of the worst sort.” Sommer says that the editors wanted to tone him down, so they took out the following sentence: “I am not sure if they are homicidal idiots or suicidal idiots.”
He felt that the biggest danger of Jahrling’s research was that it would look suspicious to other countries and would encourage them to do their own experimentation. “We could start an arms race over smallpox, and the thinking would go, ‘You could be bioengineering smallpox, so I’m going to bioengineer a smallpox, as well.’ I don’t think it would be hard to bioengineer smallpox,” he went on. “My virologist friends are always bioengineering viruses. I could see a bioengineered strain of smallpox getting into a terrorist’s hands, and that’s my fear. And then when we get a terrorist attack with smallpox, and the smallpox doesn’t respond to the vaccine, we’re in trouble.” He wanted the United States and Russia to get together to destroy their stocks, jointly scour the world for stray stocks of smallpox, and use every effort to persuade other countries to destroy them. He wanted to create an international abhorrence for any nation that would keep smallpox around. He wanted the demon cast out. “It still rankles me,” he said, “that we are giving smallpox to animals that could not get smallpox naturally, in order to protect humans, when the last time a human had smallpox was 1978, and humans shouldn’t naturally get it today. This is my circular indignation.”
I VISITED
D. A. Henderson at his home in Baltimore a little over two months after the anthrax attacks. I arrived in the late afternoon, bringing smoked salmon and a bottle of Linkwood malt whisky. Nana Henderson spread out the salmon with lemon and onion on a table in the family room. Their son Doug, who is now a composer, was there. As a teenager, Doug had traveled with his father, and had vaccinated many people himself. In the cool, dry light of a winter’s afternoon, the Hendersons and I poured out glasses of Linkwood and picked away at the salmon. D.A. talked about why people had joined the Eradication: “Some of them were looking for themselves, and some of them got involved with feeling what a difference you could make if you could end this disease.” The sky began turning to dusk. Pots of dead thyme sat on the deck, silvery and dry. “Smallpox was the only disease we know of for which there were deities,” he said. “It was the worst human disease. I don’t know of anything else that comes close.”
Later, on the subject of Peter Jahrling’s work infecting monkeys with variola, Henderson said he was not optimistic that it would lead to new drugs or vaccines. “Do we need to do the research? There are some scientists who feel it’s important and should be pursued. But is it really going to work? Peter Jahrling gave the monkeys a huge dose of virus, but it isn’t going to be very helpful for testing a new vaccine, because what we really need is an inhaled dose of smallpox in a monkey to test a vaccine, since people inhale the virus.” He sounded discouraged, emotionally drained over the fight to destroy the public stocks of smallpox. He was working for the government, and government policy was to look for new cures for smallpox, and that meant doing experiments with variola. He said that he had taken care of his emotions over the issue of destroying the known stocks of smallpox. “Everything is in neutral right now,” he said. “There is no point in my entering a battle where the cards are stacked. I’m playing along with what they’re doing. I’m asking them to pursue the research.” Henderson had gone so far as to suggest to Peter Jahrling that he try an African strain of smallpox, Congo 8, on the monkeys, because it might look more like human smallpox. “If it works, Peter, I want the credit,” he said to Jahrling.
“When the research with variola has been pursued to some reasonable point, then I want to revisit the question of destruction,” he said. “The subject should be reopened.”
He had thanked me for the smoked salmon that day. “It’s really large,” he remarked. “I wonder: is it one of the newer genetically engineered salmon? It’s fairly simple to add one gene to a salmon. Or to any organism in the lab. Will people change organisms in the lab to make them more dangerous? Can it be done? Yeah. Will it be done? Yeah, it will be done,” he said. “And there will be unexpected crises.”
ON
April 30th, 2002, a group of six experts on the spread of infectious diseases met under conditions of secrecy in a conference room at the John E. Fogarty International Center at the National Institutes of Health (the NIH), in Bethesda, Maryland. Each expert had been asked to create a model of the spread of smallpox in the United States, starting with a small number of infected people. One of the experts—Dr. Martin Meltzer of the CDC—found that smallpox could be easily controlled with ring vaccination using the traditional vaccine. He felt that the virus was not very infective in people and would be unlikely to spread fast or far. The other five experts disagreed with one another, sometimes sharply, but in general they found that smallpox would spread widely and rapidly. They argued forcefully with each other (as scientists do), but in the end, none of the experts could predict what smallpox would do—not to the satisfaction of the other experts. “Our general conclusion was that smallpox is a devastating biological weapon in an unimmunized human population,” one of the participants said. “If you look at the real-world data from a 1972 outbreak in Yugoslavia, you find that the multiplier of the virus was ten: the first infected people gave it to ten more people, on average. Basically, if you don’t catch the first guy with smallpox before he kisses his wife, it goes out of control. We could be dealing with hundreds of thousands of deaths. It will absolutely shut down international trade, and it will make 9/11 look like a cakewalk. Smallpox can bring the world to its knees.” The experts were told by NIH officials that they should not publicize their findings.
S
UPERPOX
Dr. Chen’s Viruses
UNANSWERED QUESTIONS
hung over variola, and not just the question of whether ring vaccination would work if there was a terror attack with smallpox. The more troubling question was how molecular biology would affect the future of smallpox. Poxviruses are used in laboratories all over the world precisely because they are easily engineered. Commercial kits for the process are available at no great cost. It should not be forgotten that the director of the Iraqi virus-weapons program, Dr. Hazem Ali, was a pox virologist trained in England, and one assumes that he is not the only professional bioweaponeer in the world with advanced credentials in biology.
The Australian team of mouse researchers led by Ronald Jackson and Ian Ramshaw had put the IL-4 mouse gene into mousepox and had created a superpox that appeared to break through the mice’s immunity. The Jackson-Ramshaw virus was harmless in people, but it seemed to be devastating in immunized mice.
Bioterror planners wondered: if the human IL-4 gene were put into smallpox, would it transform smallpox into a super variola that would devastate immunized humans? The Jackson-Ramshaw virus had been a narrow beam of light shining across a dark landscape of the future. It had shown dim outlines of virus weapons to come.
When an experiment gives a result, the first thing scientists do is try to repeat the experiment to see if they can get the same result. The essence of the scientific method lies in the repeatable result: if you perform an experiment in the same way, nature will do the same thing again. This is the heart of science and is the sign that an observable phenomenon in nature has been found. Would the results of the Jackson-Ramshaw experiment bear out? Could a poxvirus be engineered to crash through a vaccine?
ONE DAY
in early 2002, I parked my car in a downtown neighborhood of St. Louis and walked along an uneven sidewalk toward the St. Louis University School of Medicine. The neighborhood is humble but neat, and is largely African-American. There are row houses with porches tucked up against the street. American flags hung from several porches or were on display in windows. The school of medicine is a stately neo-Gothic brick building, trimmed with pink midwestern sandstone, and on that day it glowed with warmth in winter light.
The façade gives way to a concrete, fortresslike structure, five stories tall, with small windows, where the research laboratories are located. In a group of rooms on the fourth floor, a pox virologist named Mark Buller leads a group of researchers who do experiments with mousepox virus and with vaccinia. They work mainly with mice—the mouse is the standard animal used in biomedical research. Most of the important discoveries about how our immune systems work were made originally in experiments done with mice.
Mark Buller is a tall, lanky, self-effacing man in his fifties, a dual citizen of Canada and the United States, with curly black hair, a black mustache, intelligent brown eyes behind round glasses, and a voice that has an attractive Canadian softness. He grew up in Victoria, British Columbia. He often walks around the lab in nylon wind pants, a T-shirt, and running shoes. He keeps a spare jacket and tie hanging on the wall of his office, in case an important meeting comes up. Buller is known and respected among pox virologists, although he seems to deliberately avoid the limelight. “My goal in life is to be prominently in the shadows,” he said to me.
Buller began hearing a lot about the Jackson-Ramshaw experiment from Peter Jahrling and Richard Moyer. Right after it was published, Moyer, especially, raised alarms—he began saying, quietly, to Buller that either he or Buller should try to repeat the experiment. The Australian smallpox expert Frank Fenner had advised Jackson and Ramshaw to publish their work, partly on the grounds that nobody would really make an IL-4 smallpox, since it might be too devastating and perhaps even suicidal. In the wake of September 11th, the release of a genetically engineered smallpox into the United States did not seem quite so impossible.
Mark Buller decided to create an IL-4 mousepox, to see if it would blow through a vaccine. He wanted to get a sense of whether a human IL-4 smallpox could become a supervirus, and if so, what vaccination strategy for people would work against it. I arrived at Buller’s lab as the experiment was getting under way. I wanted to hold an engineered superpox in my hands and get a feel for where the tide of modern biology was taking us.
MARK BULLER
leaned back at his desk, his hands clasped behind his head. His office was crowded with books and papers, and there was an exercise mat on the floor. On a whiteboard on the wall, his daughter, Meghan, had drawn a caricature of him as a science nerd, with Coke-bottle spectacles, a brushy mustache, and a bunch of pens in his shirt pocket.
“If there is a bioterror release of smallpox, currently the main strategy is ring vaccination,” he said. “In order for ring vaccination to work, the vaccine has to block severe smallpox disease in people. But what if a smallpox that’s expressing IL-4 blocks people’s immune responses?”
Buller explained that his group would make four different engineered mousepox virus strains. They would all have the IL-4 gene in them, but they would be slightly different from one another. One of them would be almost the same as the Australian engineered pox. “We want to get a feeling for what the IL-4 gene does in mousepox,” Buller said. “I’ve always found that whenever I try to predict Mother Nature I’m wrong.”
Buller’s lab was a group of rooms with white floors and cluttered black counters and shelves. Four or five people were working on different projects, and it was a crowded place. In a corner, under a window, a scientist named Nanhai Chen was in the middle of the virus engineering. He was working at a counter that was three feet long and a foot and a half wide. Virus engineering doesn’t have to take up much real estate. Mousepox virus, even engineered mousepox, is harmless to humans, because the virus simply can’t grow inside the human body, so the work was safe for the people in the room.
Nanhai Chen is a quiet man in his late thirties. He grew up on a collective near Shanghai called the Red Star Farm, where his father was a farmer and where some of his sisters still live. In high school, Chen decided he liked biology, and he went on to have a fast-track career at the Institute of Virology at the Chinese Academy of Preventive Medicine in Beijing, which is probably the top virology center in China. He became an expert in the DNA of vaccinia virus. Mark Buller hired him out of China.
Nanhai Chen has a fuzzy crew cut, hands that work rapidly, wire-rimmed spectacles, and restrained manners. He and his wife, Hongdong Bai, who is also a molecular biologist, have given their children American names, Kevin and Steven. He wears only two outfits, one for winter and one for summer. His winter outfit is a blue cotton sweater, blue slacks, and white running shoes. I spent days with Chen during the time he engineered the mouse supervirus. “It’s not difficult to make this virus,” he said to me one day. “You could learn how to do it.”
A VIRUS
that has been engineered in the laboratory is called a recombinant virus. This is because its genetic material—DNA or RNA—has genes in it that come from other forms of life. These foreign genes have been inserted into the virus’s genetic material through the process of recombination. The term
construct
is also used to describe it, because the virus is constructed of parts and pieces of genetic code—it is a designer virus, with a particular purpose.
The DNA molecule is shaped like a twisted ladder, and the rungs of the ladder—the nucleotides—can hold vast amounts of information, the code of life. A gene is a short stretch of DNA, typically about a thousand letters long, that holds the recipe for a protein or a group of related proteins. The total assemblage of an organism’s genetic code—its full complement of DNA, comprising all its genes—is the organism’s genome. Poxviruses have long genomes, at least for viruses. A pox genome typically holds between 150,000 and 200,000 letters of code, in a spaghettilike knot of DNA that is jammed into the dumbbell structure at the center of the pox particle. The poxvirus’s genome contains about two hundred genes—that is, the pox particle has around two hundred different proteins. Some of them are locked together in the mulberry structure of the particle. Other proteins are released by the pox particle, and they confuse or undermine the immune system of the host, so that the virus can amplify itself more easily. Poxviruses specialize in releasing signaling proteins that derange control systems in the host. For example, insect poxes release signals that cause an infected caterpillar to stop developing and grow into a bag packed with virus.
The human genome, coiled up in the chromosomes of every typical cell in the human body, consists of about three billion letters of DNA, or perhaps forty thousand active genes. (No one is certain how many active genes human DNA has in it.) The letters in the human genome would fill around ten thousand copies of
Moby-Dick:
a person is more complicated than a pox.
The IL-4 gene holds the recipe for a common immune-system compound called interleukin-4, a cytokine that in the right amounts normally helps a person or a mouse fight off an infection by stimulating the production of antibodies. If the gene for IL-4 is added to a poxvirus, it will cause the virus to make IL-4. It starts signaling the immune system of the host, which becomes confused and starts making more antibodies. But, paradoxically, if too many antibodies are made, another type of immunity goes
down—
cellular immunity. Cellular immunity is provided by numerous kinds of white blood cells. When a person dies of AIDS, it is because a key part of his or her cellular immunity (the population of CD4 cells) has been destroyed by HIV infection. The engineered mousepox seems to create a kind of instant AIDS-like immune suppression in a mouse right at the moment when the mouse needs this type of immunity the most to fight off an exploding pox infection. An engineered smallpox that triggered an AIDS-like immune suppression in people would be no joke.
TO CREATE
a construct virus, you start with a cookbook and some standard ingredients. The basic raw ingredient in Chen’s experiment was a vial of frozen natural wild-type mousepox virus, which sat in a freezer around the corner from his work area. The other basic ingredient was the mouse IL-4 gene. Chen’s cooking, so to speak, involved splicing the gene into the DNA of the poxvirus and then making sure the resulting construct virus worked as it was supposed to.
Chen ordered the IL-4 gene through the Internet. It cost sixty-five dollars, and it came by regular mail at Mark Buller’s lab in November 2001, from the American Type Culture Collection, a nonprofit institute in Manassas, Virginia, where strains of micro-organisms and common genes are kept in archives. The gene arrived in a small, brown glass bottle with a screw top. Inside the bottle was a pinch of tan-colored dry bacteria
—E. coli,
bacteria that live in the human gut. The bacterial cells contained small rings of extra DNA called plasmids, and the plasmids held the IL-4 gene. The IL-4 gene is a short piece of DNA, only about four hundred letters long, and it is one of the most common genes used in medical research. To date, more than sixteen thousand scientific papers have been written on the IL-4 gene.
The standard cookbook for virus engineering is a four-volume series in ring binders with bright red covers, entitled
Current Protocols in Molecular Biology,
published by John Wiley and Sons. Nanhai Chen took me to a shelf in the lab, pulled down volume three of
Current Protocols,
and opened it to section 4, protocol 16.15, which describes exactly how to put a gene into a poxvirus. If anyone puts the IL-4 gene into smallpox, they may well do it by the book. “This cannot be classified,” Chen said, running his finger over the recipe. “No one ever thought this could be used for making a weapon. The only difficult part of it is getting the smallpox. If somebody has smallpox, all the rest of the information for engineering it is public.”
“Are you personally worried about engineered smallpox?”
“Yes, I am,” he answered, holding the cookbook open as he spoke. “I was talking last week with my mentor in China. His name is Dr. Hou, and he’s a very famous virologist in China. He told me the Russians have a genetically modified and weaponized smallpox. My mentor didn’t say where he learned this, but I think he has good access to information, and I think it is probably true. Smallpox was all over the world thirty years ago. It could be anywhere today. It’s not hard to keep back a little bit of smallpox in a freezer.”
I will omit the subtleties of Chen’s work for the sake of general readers, but the outline of a recipe for making the biological equivalent of an atomic bomb is in these pages. I would hesitate to publish it, except that it’s already known to biologists; it just isn’t known to everyone else. It doesn’t take a rocket scientist to make a superpox. You do need training, though, and there is a subtle art to virus engineering. One becomes better at it with experience. Virus engineering takes skill with the hands, and in time you develop speed. Chen felt that with a little luck he could engineer any sort of typical construct poxvirus in about four weeks.
Chen took the little brown glass bottle of dry bacteria that contained the IL-4 gene and cultured the bacteria in vials. Then he added a detergent that broke up the bacteria, and he spun the material in a centrifuge. The cell debris fell to the bottom of the tubes, but the DNA plasmid rings remained suspended and floating in the liquid. He ran this liquid through a tiny filter. The filter trapped the DNA that held the IL-4 gene. He ended up with a few drops of clear liquid.
Next, Chen spliced some short bits of DNA, known as promoters and flanking sequences into the plasmid rings. He did this basically by adding drops of liquid. Promoters signal a gene to begin making protein. The various promoters were going to cause the strains of engineered mousepox to express the IL-4 protein in differing amounts and at different times in the life cycle of the virus as it replicated in cells.