Blue whirl
Bloo werl n.
A swirling flame that appears in fuel floating on the surface of water and glows blue.

An unfortunate mix of electricity and bourbon has led to a new discovery. After lightning hit a Jim Beam warehouse in 2003, a nearby lake was set ablaze when the distilled spirit spilled into the water and ignited. Spiraling tornadoes of fire leapt from the surface. In a laboratory experiment inspired by the conflagration, a team of researchers produced a new, efficiently burning fire tornado, which they named a blue whirl.
To re-create the bourbon-fire conditions, the researchers, led by Elaine Oran of the University of Maryland in College Park, ignited liquid fuel floating on a bath of water. They surrounded the blaze with a cylindrical structure that funneled air into the flame to create a vortex with a height of about 60 centimeters. Eventually, the chaotic fire whirl calmed into a blue, cone-shaped flame just a few centimeters tall, the scientists report online August 4 in Proceedings of the National Academy of Sciences.

“Firenadoes” are known to appear in wildfires, when swirling winds and flames combine to form a hellacious, rotating inferno. They burn more efficiently than typical fires, as the whipping winds mix in extra oxygen, which feeds the fire. But the blue whirl is even more efficient; its azure glow indicates complete combustion, which releases little soot, or uncombusted carbon, to the air.

The soot-free blue whirls could be a way of burning off oil spills on water without adding much pollution to the air, the researchers say, if they can find a way to control them in the wild.

Editor’s note: When reporting results from the functional MRI scans of dogs’ brains, left and right were accidentally reversed in all images, the researchers report in a correction posted April 7 in Science. While dogs and most humans use different hemispheres of the brain to process meaning and intonation — instead of the same hemispheres, as was suggested — lead author Attila Andics says the more important finding still stands: Dogs’ brains process different aspects of human speech in different hemispheres.
Dogs process speech much like people do, a new study finds. Meaningful words like “good boy” activate the left side of a dog’s brain regardless of tone of voice, while a region on the right side of the brain responds to intonation, scientists report in the Sept. 2 Science.

Similarly, humans process the meanings of words in the left hemisphere of the brain, and interpret intonation in the right hemisphere. That lets people sort out words that convey meaning from random sounds that don’t. But it has been unclear whether language abilities were a prerequisite for that division of brain labor, says neuroscientist Attila Andics of Eötvös Loránd University in Budapest.

Dogs make ideal test subjects for understanding speech processing because of their close connection to humans. “Humans use words towards dogs in their everyday, normal communication, and dogs pay attention to this speech in a way that cats and hamsters don’t,” says Andics. “When we want to understand how an animal processes speech, it’s important that speech be relevant.”
Andics and his colleagues trained dogs to lie still for functional MRI scans, which reveal when and where the brain is responding to certain cues. Then the scientists played the dogs recordings of a trainer saying either meaningful praise words like “good boy,” or neutral words like “however,” either in an enthusiastic tone of voice or a neutral one.
The dogs showed increased activity in the left sides of their brains in response to the meaningful words, but not the neutral ones. An area on the right side of the brain reacted to the intonation of those words, separating out enthusiasm from indifference.

When the dogs heard praising words in an enthusiastic tone of voice, neural circuits associated with reward became more active. The dogs had the same neurological response to an excited “Good dog!” as they might to being petted or receiving a tasty treat. Praise words or enthusiastic intonation alone didn’t have the same effect.

Humans stand out from other animals in their ability to use language — that is, to manipulate sequences of sounds to convey different meanings. But the new findings suggest that the ability to hear these arbitrary sequences of sound and link them to meaning isn’t a uniquely human ability.

“I love these results, as they point to how well domestication has shaped dogs to use and track the very same cues that we use to make sense of what other people are saying,” says Laurie Santos, a cognitive psychologist at Yale University.

While domestication made dogs more attentive to human speech, humans have been close companions with dogs for only 30,000 years. That’s too quickly for a trait like lateralized speech processing to evolve, Andics thinks. He suspects that some older underlying neural mechanism for processing meaningful sounds is present in other animals, too.

It’s just hard to test in other species, he says — in part because cats don’t take as kindly to being put inside MRI scanners and asked to hold still.

A beautiful but unproved theory of particle physics is withering in the harsh light of data.

For decades, many particle physicists have devoted themselves to the beloved theory, known as supersymmetry. But it’s beginning to seem that the zoo of new particles that the theory predicts —the heavier cousins of known particles — may live only in physicists’ imaginations. Or if such particles, known as superpartners, do exist, they’re not what physicists expected.

New data from the world’s most powerful particle accelerator — the Large Hadron Collider, now operating at higher energies than ever before — show no traces of superpartners. And so the theory’s most fervent supporters have begun to pay for their overconfidence — in the form of expensive bottles of brandy. On August 22, a group of physicists who wagered that the LHC would quickly confirm the theory settled a 16-year-old bet. In a session at a physics meeting in Copenhagen, theoretical physicist Nima Arkani-Hamed ponied up, presenting a bottle of cognac to physicists who bet that the new particles would be slow to materialize, or might not exist at all.
Whether their pet theories are right or wrong, many theoretical physicists are simply excited that the new LHC data can finally anchor their ideas to reality. “Of course, in the end, nature is going to tell us what’s true,” says theoretical physicist Yonit Hochberg of Cornell University, who spoke on a panel at the meeting.

Supersymmetry is not ruled out by the new data, but if the new particles exist, they must be heavier than scientists expected. “Right now, nature is telling us that if supersymmetry is the right theory, then it doesn’t look exactly like we thought it would,” Hochberg says.
Since June 2015, the LHC, at the European particle physics lab CERN near Geneva, has been smashing protons together at higher energies than ever before: 13 trillion electron volts. Physicists had been eager to see if new particles would pop out at these energies. But the results have agreed overwhelmingly with the standard model, the established theory that describes the known particles and their interactions.

It’s a triumph for the standard model, but a letdown for physicists who hope to expose cracks in that theory. “There is a low-level panic,” says theoretical physicist Matthew Buckley of Rutgers University in Piscataway, N.J. “We had a long time without data, and during that time many theorists thought up very compelling ideas. And those ideas have turned out to be wrong.”

Physicists know that the standard model must break down somewhere. It doesn’t explain why the universe contains more matter than antimatter, and it fails to pinpoint the origins of dark matter and dark energy, which make up 95 percent of the matter and energy in the cosmos.

Even the crowning achievement of the LHC, the discovery of the Higgs boson in 2012 (SN: 7/28/2012, p. 5), hints at the sickness within the standard model. The mass of the Higgs boson, at 125 billion electron volts, is vastly smaller than theory naïvely predicts. That mass, physicists worry, is not “natural” — the factors that contribute to the Higgs mass must be finely tuned to cancel each other out and keep the mass small (SN Online: 10/22/13).

Among the many theories that attempt to fix the standard model’s woes, supersymmetry is the most celebrated. “Supersymmetry was this dominant paradigm for 30 years because it was so beautiful, and it was so perfect,” says theoretical physicist Nathaniel Craig of the University of California, Santa Barbara. But supersymmetry is becoming less appealing as the LHC collects more collisions with no signs of superpartners.

Supersymmetry solves three major problems in physics: It explains why the Higgs is so light; it provides a particle that serves as dark matter; and it implies that the three forces of the standard model (electromagnetism and the weak and strong nuclear forces) unite into one at high energies.

If a simple version of supersymmetry is correct, the LHC probably should have detected superpartners already. As the LHC rules out such particles at ever-higher masses, retaining the appealing properties of supersymmetry requires increasingly convoluted theoretical contortions, stripping the idea of some of the elegance that first persuaded scientists to embrace it.
“If supersymmetry exists, it is not my parents’ supersymmetry,” says Buckley. “That kind of means it can’t be the most compelling version.”

Still, many physicists are adopting an attitude of “keep calm and carry on.” They aren’t giving up hope that evidence for the theory — or other new particle physics phenomena — will show up soon. “I am not yet particularly worried,” says theoretical physicist Carlos Wagner of the University of Chicago. “I think it’s too early. We just started this process.” The LHC has delivered only 1 percent of the data it will collect over its lifetime. Hopes of quickly finding new phenomena were too optimistic, Wagner says.
Experimental physicists, too, maintain that there is plenty of room for new discoveries. But it could take years to uncover them. “I would be very, very happy if we were able to find some new phenomena, some new state of matter, within the first two or three years” of running the LHC at its boosted energy, Tiziano Camporesi of the LHC’s CMS experiment said during a news conference at the International Conference on High Energy Physics, held in Chicago in August. “That would mean that nature has been kind to us.”

But other LHC scientists admit they had expected new discoveries by now. “The fact that we haven’t seen something, I think, is in general quite surprising to the community,” said Guy Wilkinson, spokesperson for the LHCb experiment. “This isn’t a failure — this is perhaps telling us something.” The lack of new particles forces theoretical physicists to consider new explanations for the mass of the Higgs. To be consistent with data, those explanations can’t create new particles the LHC should already have seen.

Some physicists — particularly those of the younger generations — are ready to move on to new ideas. “I’m personally not attached to supersymmetry,” says David Kaplan of Johns Hopkins University. Kaplan and colleagues recently proposed the “relaxion” hypothesis, which allows the Higgs mass to change — or relax — as the universe evolves. Under this theory, the Higgs mass gets stuck at a small value, never reaching the high mass otherwise predicted.

Another idea, which Craig favors, is a family of theories by the name of “neutral naturalness.” Like supersymmetry, this idea proposes symmetries of nature that solve the problem of the Higgs mass, but it doesn’t predict new particles that should have been seen at the LHC. “The theories, they’re not as beautiful as just simple supersymmetry, but they’re motivated by data,” Craig says.

One particularly controversial idea is the multiverse hypothesis. There may be innumerable other universes, with different Higgs masses in each. Perhaps humans observe such a light Higgs because a small mass is necessary for heavy elements like carbon to be produced in stars. People might live in a universe with a small Higgs because it’s the only type of universe life can exist in.

It’s possible that physicists’ fears will be realized — the LHC could deliver the Higgs boson and nothing else. Such a result would leave theoretical physicists with few clues to work with. Still, says Hochberg, “if that’s the case, we’ll still be learning something very deep about nature.”

WASHINGTON — A quantum internet could one day allow ultrasecure communications worldwide — but first, scientists must learn to tame unruly quantum particles such as electrons and photons. Several new developments in quantum technology, discussed at a recent meeting, have brought scientists closer to such mastery. Scientists are now teleporting particles’ properties across cities, satellite experiments are gearing up for quantum communications in space, and other scientists are developing ways to hold quantum information in memory.

In one feat, scientists achieved quantum teleportation across long distances through metropolitan areas. Quantum teleportation transfers quantum properties of one particle to another instantaneously. (It doesn’t allow for faster-than-light communication, though, because additional information has to be sent through standard channels.)
Using a quantum network in Calgary, scientists teleported quantum states of photons over 6.2 kilometers. “It’s one step towards … achieving a global quantum network,” says Raju Valivarthi of the University of Calgary in Canada, who presented the result at the International Conference on Quantum Cryptography, QCrypt, on September 12.

A second group of scientists recently teleported photons using a quantum network spread through the city of Hefei, China. The two teams published their results online September 19 in Nature Photonics.

The weird properties of quantum particles make quantum communication possible: They can be in two places at once, or can have their properties linked through quantum entanglement. Tweak one particle in an entangled pair, and you can immediately seem to affect the other — what Albert Einstein called “spooky action at a distance.” Using quantum entanglement, people can securely exchange quantum keys — codes which can be used to encrypt top-secret messages. (SN: 11/20/10, p. 22). Any eavesdropper spying on the quantum key exchange would be detected, and the keys could be thrown out.

In practice, quantum particles can travel only so far. As photons are sent back and forth through optical fibers, many are lost along the way. But certain techniques can be used to expand their range. Quantum teleportation systems could be used to create quantum repeaters, which could be chained together to extend networks farther. But in order to function, quantum repeaters would also require a quantum memory to store entanglement until all the links in the chain are ready, says Ronald Hanson of Delft University of Technology in the Netherlands. Using a system based on quantum entanglement of electrons in diamond chips, Hanson’s team has developed a quantum memory by transferring the entanglement of the electrons to atomic nuclei for safekeeping, he reported at QCrypt on September 15.

Satellites could likewise allow quantum communication from afar. In August, China launched a satellite to test quantum communication from space; other groups are also studying techniques for sending delicate quantum information to space and back again (SN Online: 6/5/16), beaming up photons through free space instead of through optical fibers. “A free-space link is essential if you want to go to real long distance,” Giuseppe Vallone of the University of Padua in Italy said in a session at QCrypt on September 14. Particles can travel farther when sent via quantum satellite — due to the emptiness of space, fewer photons are absorbed or scattered away.
Quantum networks could also benefit from processes that allow the use of scaled-down “quantum fingerprints” of data, to compare files without sending excess data, Feihu Xu of MIT reported at QCrypt on September 12. To check if two files are identical — for example, in order to find illegally pirated movies — one might compare all the bits in each file. But in fact, a subset of the bits — or a fingerprint — can do the job well. By harnessing the power of quantum mechanics, Xu and colleagues were able to compare messages using less information than classical methods require.

The quantum internet relies on the principles of quantum mechanics, which modern-day physicists generally accept — spooky action and all. In 2015, scientists finally confirmed that a key example of quantum weirdness is real, with a souped-up version of a test known as a Bell test, which closed loopholes that had weakened earlier Bell tests (SN: 9/19/15, p. 12). Loophole-free Bell tests were necessary to squelch any lingering doubts, but no one expected any surprises, says Charles Bennett of the IBM Thomas J. Watson Research Center in Yorktown Heights, N.Y. “In a certain sense it’s beating a dead horse.”

But Bell tests have applications for the quantum internet as well — they are a foundation of an even more secure type of quantum communication, called device-independent quantum key distribution. Typically, secure exchanges of quantum keys require that the devices used are trustworthy, but device-independent methods do away with this requirement. This is “the most safe way of quantum communication,” says Hanson. “It does not make any assumptions about the internal workings of the device.”

This issue marks the second year that Science News has reached out to science notables and asked: Which up-and-coming scientist is making a splash? Whose work impresses you? Tell us about early- to mid-career scientists who have the potential to change their fields and the direction of science more generally.

This year, we expanded the pool of people we asked. We reached out to Nobel laureates again and added recently elected members of the National Academy of Sciences. That allowed us to consider shining lights from a much broader array of fields, from oceanography and astronomy to cognitive psychology. Another difference this year: We spent time face-to-face with many of those selected, to get a better sense of them both as scientists and as people.
The result is the SN 10, a collection of stories not only about science, but also about making a life in science. They are stories of people succeeding because they have found what they love, be it working in the lab on new ways to probe molecular structures or staring up to the stars in search of glimmers of the early universe. In my interviews with chemist Phil Baran, I was struck by his drive to do things in new ways, whether devising chemical reactions or developing ideas about how to fund research. (If you can, he says, go private.) Laura Sanders, who met with neuroscientist Jeremy Freeman, was intrigued by his way of seeing a problem (siloed data that can’t be easily shared or analyzed) and figuring out solutions, even if those solutions were outside his area of expertise.

Of course, there are many ways to identify noteworthy scientists — and there’s plenty more fodder out there for future years. Our approach was to seek standouts, asking who deserved recognition for the skill of their methods, the insights of their thinking, the impacts of their research. Not all of the SN 10’s work has made headlines, but they all share something more important: They are participants in building the science of the future.

Notably, many of them do basic research. I think that’s because it’s the type of work that other scientists notice, even if it’s not always on the radar of the general public. But that’s where fundamental advances are often made, as scientists explore the unknown.

That edge of what’s known is where Science News likes to explore, too. Such as the bet-ending, head-scratching results from the Large Hadron Collider, which have failed to reveal the particles that the equations of supersymmetry predict. As Emily Conover reports in “Supersymmetry’s absence at LHC puzzles physicists,” that means that either the theory must be more complicated than originally thought, or not true, letting down those who looked to supersymmetry to help explain a few enduring mysteries, from the nature of dark matter to the mass of the Higgs boson.

Other mysteries may be closer to a solution, as Sanders reports in “New Alzheimer’s drug shows promise in small trial.” A new potential treatment for Alzheimer’s disease reduced amyloid-beta plaques in patients. It also showed hints of improving cognition. That’s standout news, a result built on decades of basic research by many, many bright young scientists.

In smart homes of the future, computers may identify inhabitants and cater to their needs using a tool already at hand: Wi-Fi. Human bodies partially block the radio waves that carry the wireless signal between router and computer. Differences in shape, size and even gait among household members yield different patterns in the received Wi-Fi signals. A computer can analyze the signals to distinguish dad from mom, according to a report posted online August 11 at arXiv.org.

Scientists built an algorithm that was nearly 95 percent accurate when attempting to discern two adults walking between a wireless router and a computer. For six people, accuracy fell to about 89 percent. Scientists tested the setup on men and women of various sizes, but it should work with children as well, says study coauthor Bin Guo of Northwestern Polytechnical University in Xi’an, China.

In a home rigged with Wi-Fi and a receiver, the system could eventually identify family members and tailor heating and lighting to their preferences — maybe even cue up a favorite playlist.

Nature’s rarest type of atomic nucleus is not giving up its secrets easily.

Scientists looking for the decay of an unusual form of the element tantalum, known as tantalum-180m, have come up empty-handed. Tantalum-180m’s hesitance to decay indicates that it has a half-life of at least 45 million billion years, Bjoern Lehnert and colleagues report online September 13 at arXiv.org. “The half-life is longer than a million times the age of the universe,” says Lehnert, a nuclear physicist at Carleton University in Ottawa. (Scientists estimate the universe’s age at 13.8 billion years.)
Making up less than two ten-thousandths of a percent of the mass of the Earth’s crust, the metal tantalum is uncommon. And tantalum-180m is even harder to find. Only 0.01 percent of tantalum is found in this state, making it the rarest known long-lived nuclide, or variety of atom.

Tantalum-180m is a bit of an oddball. It is what’s known as an isomer — its nucleus exists in an “excited,” or high-energy, configuration. Normally, an excited nucleus would quickly drop to a lower energy state, emitting a photon — a particle of light — in the process. But tantalum-180m is “metastable” (hence the “m” in its name), meaning that it gets stuck in its high-energy state.
Tantalum-180m is thought to decay by emitting or capturing an electron, morphing into another element — either tungsten or hafnium — in the process. But this decay has never been observed. Other unusual nuclides, such as those that decay by emitting two electrons simultaneously, can have even longer half-lives than tantalum-180m. But tantalum-180m is unique — it is the longest-lived isomer found in nature.
“It’s a very interesting nucleus,” says nuclear physicist Eric Norman of the University of California, Berkeley, who was not involved with the study. Scientists don’t have a good understanding of such unusual decays, and a measurement of the half-life would help scientists pin down the details of the process and the nucleus’ structure.
Lehnert and colleagues observed a sample of tantalum with a detector designed to catch photons emitted in the decay process. After running the experiment for 176 days, and adding in data from previous incarnations of the experiment, the team saw no evidence of decay. The half-life couldn’t be shorter than 45 million billion years, the scientists determined, or they would have seen some hint of the process. “They did a state-of-the-art measurement,” says Norman. “It’s a very difficult thing to see.”

The presence of tantalum-180m in nature is itself a bit of a mystery, too. The element-forging processes that occur in stars and supernovas seem to bypass the nuclide. “People don’t really understand how it is created at all,” says Lehnert.

Tantalum-180m is interesting as a potential energy source, says Norman, although “it’s kind of a crazy idea.” If scientists could find a way to tap the energy stored in the excited nucleus by causing it to decay, it might be useful for applications like nuclear lasers, he says.

Motors too small to see with the eye may soon have the power to drive innovations in chemistry, biology and computing. Three creators of such nanoscopic machines were honored October 5 with the Nobel Prize in chemistry.

Sharing the prize of 8 million Swedish kronor (about $930,000) equally are Jean-Pierre Sauvage, J. Fraser Stoddart and Bernard Feringa. “If you had to choose three people at the top of the field, that’s it. These are the men,” says James Tour, a na
Recognition of the burgeoning field of molecular motors will draw more money and inspire children to become scientists, says Donna Nelson, an organic chemist at the University of Oklahoma in Norman and the president of the American Chemical Society. “It will benefit not only these three chemists, it will benefit the entire field of chemistry.”
Chemists and physicists have envisioned molecular machines since at least the 1960s, but were never able to reliably produce complex structures. Then in 1983, Sauvage, of the University of Strasbourg in France, devised a method for making interlocking molecular rings, or catenanes. Sauvage’s molecular chain set the stage for the rest of the field (SN: 9/8/90, p. 149).

Stoddart, of Northwestern University in Evanston, Ill., improved the efficiency so that he could produce large quantities of molecular machines, starting in 1991 with rings clipped around a central axle. That structure is known as a rotaxane. He and colleagues learned to control the slide of the rings along the axle, making a simple molecular switch. Such switches could be used to create molecular computers or drug delivery systems. Stoddart showed in 2000 that it was possible to make molecular “muscles” using interlocking rings and axles. Stoddart and colleagues have since devised molecular elevators and pumps based on the same molecules.
Feringa, of the University of Groningen in the Netherlands, ramped things up another notch in 1999 by building the first molecular motor. Things move so differently at the molecular scale that many researchers weren’t sure anyone could precisely control the motion of molecular motors, says R. Dean Astumian of the University of Maine in Orono. Feringa’s innovation was to devise asymmetric molecules that would spin in one direction when hit with a pulse of light.

Up to 50,000 of the motors could span the width of a human hair, says Tour. Alone, one of the spinning motors doesn’t pack much punch (SN: 2/7/04, p. 94), but harnessed together in large numbers the little motors can do big work, he says. Groups of the whirring motors powered by light can rotate a glass rod thousands of times their size and do other work on a macroscopic scale. Feringa also harnessed his motors into a four-wheel-drive “nanocar” (SN: 12/17/11, p. 8).

The process of making molecular machines has improved drastically over recent decades, thanks in large part to the work of the three newly christened laureates, says Rigoberto Advincula, a chemist at Case Western Reserve University in Cleveland. Scientists have a better understanding of how to construct molecules that more reliably bend, loop and connect to form shapes. “You don’t have tweezers to put them together,” he says. “You template the reaction so that the thread to goes through the ring. That then makes it easier for the two thread ends to meet each other.” New techniques have also allowed the production of more intricate shapes. Further development will bring these processes to even bigger scales, allowing for the design of molecular machines for everything from energy harvesting to building protein complexes, Advincula says.
Such applications are still on the horizon and no one really knows what sorts of machines chemists can make from molecules yet. When people question Feringa about what his molecular motors can be used for, he “feels a bit like the Wright brothers” when people asked them after their first flight why they needed a flying machine, he said during a telephone call during the announcement of the prize. There are “endless opportunities,” including nanomachines that can seek and destroy tumor cells or deliver drugs to just the cells that need them, Feringa speculated.

Stoddart, who was born in Edinburgh and moved to the United States in 1997, applauded the Nobel committee for recognizing “a piece of chemistry that is extremely fundamental in its making and being.” Sauvage, in particular, created a new type of molecular bond in order to forge his chain, Stoddart said during a news conference. “New chemical compounds are probably several thousand a day worldwide,” he said. “New chemical reactions, well, maybe a dozen or two a month. Maybe I go over the top there. But new bonds, they are few and far between. They are really the blue moons. So I think that’s what’s being recognized, more than anything.”

Two trillion galaxies. That’s the latest estimate for the number of galaxies that live — or have lived — in the observable universe, researchers report online October 10 at arXiv.org. This updated headcount is roughly 10 times greater than previous estimates and suggests that there are a lot more galaxies out there for future telescopes to explore.

Hordes of relatively tiny galaxies, weighing as little as 1 million suns, are responsible for most of this tweak to the cosmic census. Astronomers haven’t directly seen these galaxies yet. Christopher Conselice, an astrophysicist at the University of Nottingham in England, and colleagues combined data from many ground- and space-based telescopes to look at how the number of galaxies in a typical volume of the universe has changed over much of cosmic history. They then calculated how many galaxies have come and gone in the universe.

The galactic population has dwindled over time, as most of those 2 trillion galaxies collided and merged to build larger galaxies such as the Milky Way, the researchers suggest. That’s in line with prevailing ideas about how massive galaxies have been assembled. Seeing many of these remote runts, however, is beyond the ability of even the next generation of telescopes. “We will have to wait at least several decades before even the majority of galaxies have basic imaging,” the researchers write.

Crucial immune system proteins that make it harder for viruses to replicate might also help the attackers avoid detection, three new studies suggest. When faced with certain viruses, the proteins can set off a cascade of cell-to-cell messages that destroy antibody-producing immune cells. With those virus-fighting cells depleted, it’s easier for the invader to persist inside the host’s body.

The finding begins to explain a longstanding conundrum: how certain chronic viral infections can dodge the immune system’s antibody response, says David Brooks, an immunologist at the University of Toronto not involved in the research. The new studies, all published October 21 in Science Immunology, pin the blame on the same set of proteins: type 1 interferons.
Normally, type 1 interferons protect the body from viral siege. They snap into action when a virus infects cells, helping to activate other parts of the immune system. And they make cells less hospitable to viruses so that the foreign invaders can’t replicate as easily.

But in three separate studies, scientists tracked mice’s immune response when infected with lymphocytic choriomeningitis virus, or LCMV. In each case, type 1 interferon proteins masterminded the loss of B cells, which produce antibodies specific to the virus that is being fought. Normally, those antibodies latch on to the target virus, flagging it for destruction by other immune cells called T cells. With fewer B cells, the virus can evade capture for longer.

The proteins’ response “is driving the immune system to do something bad to itself,” says Dorian McGavern, an immunologist at the National Institute of Neurological Disorders and Stroke in Bethesda, Md., who led one of the studies.

The interferon proteins didn’t directly destroy the B cells; they worked through middlemen instead. These intermediaries differed depending on factors including the site of infection and how much of the virus the mice received.
T cells were one intermediary. McGavern and his colleagues filmed T cells actively destroying their B cell compatriots under the direction of the interferon proteins. When the scientists deleted those T cells, the B cells didn’t die off even though the interferons were still hanging around.
Another study found that the interferons were sending messages not just through T cells, but via a cadre of other immune cells, too. Those messages told B cells to morph into cells that rapidly produce antibodies for the virus. But those cells die off within a few days instead of mounting a longer-term defense.

That strategy could be helpful for a short-term infection, but less successful against a chronic one, says Daniel Pinschewer, a virologist at the University of Basel in Switzerland who led that study. Throwing the entire defense arsenal at the virus all at once leaves the immune system shorthanded later on.

But interferon activity could prolong even short-term viral infections, a third study showed. There, scientists injected lower doses of LCMV into mice’s footpads and used high-powered microscopes to watch the infection play out in the lymph nodes. In this case, the interferon stifled B cells by working through inflammatory monocytes, white blood cells that rush to infection sites.

“The net effect is beneficial for the virus,” says Matteo Iannacone, an immunologist at San Raffaele Scientific Institute in Milan who led the third study. Sticking around even a few days longer gives the virus more time to spread to new hosts.

Since all three studies looked at the same virus, it’s not yet clear whether the mechanism extends to other viral infections. That’s a target for future research, Iannacone says. But Brooks thinks it’s likely that other viruses that dampen antibody response (like HIV and hepatitis C) could also be exploiting type 1 interferons.