Discovery of natural antibody offers hope for a near-universal flu vaccine

Every year in the lead up to flu season, those at high risk of infection, such as the young, the elderly and those who are immune-compromised, head off to the doctor for a jab in the hopes it will protect them from the flu. However, influenza vaccines have a number of shortcomings that means even those who have been vaccinated may still get influenza. Researchers at the Scripps Research Institute and Dutch biopharmaceutical company Crucell have now found a broadly acting antibody that could lead to a single, near-universal flu vaccine to replace annually changing vaccines.

The high mutation rate of the influenza virus means that any particular influenza vaccine will usually grant protection for a few years at most. So every year, the World Health Organization predicts which strains of the virus are most likely to be circulating in the next year, allowing pharmaceutical companies to develop vaccines that will provide the best immunity against these strains. But with the large number of strains and the fact it takes pharmaceutical manufacturers six months to formulate and produce the millions of doses required, a new or overlooked strain can become prominent in the interim, meaning that even those who have been vaccinated may become infected.

Overcoming basic flu-virus defense mechanism

Attempts to create a vaccine that works against a wide set of strains and therefore provides protection against unforeseen strains have encountered difficulties relating to the structures that hold the virus itself. These spherical or filamentous envelopes are studded with mushroom-shaped hemagglutinin (HA) proteins, whose more accessible outer structures effectively serve as decoys for a normal antibody response.

"The outer loops on the HA head seem to draw most of the antibodies, but in a given strain these loops can mutate to evade an antibody response within months," said Ian Wilson, who is the Hansen Professor of Structural Biology and a member of the Skaggs Institute for Chemical Biology at Scripps Research.

This means that antiviral drugs aimed at these and other viral targets will also lose effectiveness as flu populations evolve. The researchers therefore sought to find and attack structures on flu viruses that are relatively unvarying and functionally important.

After sifting through the blood of people who had been immunized with flu vaccines, Crucell's Jaap Goudsmit discovered an antibody called CR6261 that bound to one such vulnerable structure. In mice, Goudsmit's team found that an injection of CR6261 could prevent or cure an otherwise-lethal infection by about half of flu viruses. These included H1 viruses such as H1N1, strains of which were responsible for the 1918 Spanish Flu and 2009 Swine Flu global pandemics.

The Crucell researchers approached Wilson, whose team determined the three-dimensional molecular structure of CR6261 and its binding site on HA, which was reported in Science in 2009. That binding site, or "epitope," turned out to be on HA's lower, less-accessible stalk portion and the binding of CR6261 to that region apparently interferes with flu viruses' ability to deliver their genetic material into host cells and start a new infection.

Not good enough

Not content with that, the Crucell researchers subsequently set about looking for an antibody that could neutralize all of the remaining flu viruses unaffected by CR6261. They recently found success with one called CR8020, which they say powerfully neutralizes a range of human-affecting flu viruses, including H3 and H7 subtypes, in lab-dish tests and in mice.

Utilizing the same technique used with CR6261, the researchers were able to determine the antibody's structure and its precise epitope on the viral HA protein.

"It's even lower on the HA stalk than the CR6261 epitope; in fact it's closer to the viral envelope than any other influenza antibody epitope we've ever seen," said Damian Ekiert, a graduate student in the Scripps Research Kellogg School of Science and Technology who is working in the Wilson laboratory.

Crucell is about to begin tests of the CR6261 antibody in human volunteers and expects to eventually begin similar trials of CR8020. If those trials succeed, aside from a vaccine the two antibodies could be combined and used in a "passive immunotherapy" approach.

"This would mainly be useful as a fast-acting therapy against epidemic or pandemic influenza viruses," said Wilson. "The ultimate goal is an active vaccine that elicits a robust, long-term antibody response against those vulnerable epitopes; but developing that is going to be a challenging task."

The Scripps Research and Crucell team's paper, "A Highly Conserved Neutralizing Epitope on Group 2 Influenza A Viruses," is published in the journal Science Express.

Source: Gizmag

Researchers Build the First Living Laser, Using Human Cells and Jellyfish Protein

Researchers at Harvard Medical School and Massachusetts General Hospital built a living laser partly to study interactions between electronic and biological systems, and partly out of sheer curiosity. The world’s first biological laser, made from a single living cell, could lead to better microscope imaging inside the body and even targeted light therapies, researchers say.

A single human cell engineered to express green fluorescent protein can be used to amplify photons into super-short pulses of laser light, the researchers say.

Lasers consist of a gain medium, the source of optical gain within the laser which absorbs external energy and excites atoms or molecules into a more energized state, inside an optical cavity. Most lasers use semiconductors, crystals or gases as a gain medium. In this case, the researchers used green fluorescent protein (GFP).

First, the researchers filled an inch-long cylinder with a GFP solution, and placed mirrors at each end. They pulsed it with light and confirmed the GFP solution could amplify the input energy into short pulses of laser emissions, according to anews release from Mass. General. This proved GFP could serve as the laser’s gain medium. Green fluorescent protein, isolated from jellyfish, will emit green light when it is exposed to blue light.

Then the team engineered human embryonic kidney cells to produce GFP, and placed a single cell between two mirrors, just 20 micrometers apart. The researchers flooded the cell with blue light, and the cell lit up. The mirrors served as the optical cavity, allowing light to bounce through the cell many times, amplifying it into a coherent green beam that was visible to the naked eye.

Living Laser Schematic: When a single biological cell genetically programmed to produce green fluorescent protein is placed inside an optical resonator consisting of two parallel mirrors separated by 20 µm (0.02 mm), the cell can generate green laser light.  Nature Photonics/Malte Gather, Wellman Center for Photomedicine, Massachusetts General Hospital

The cell’s spherical shape acted as a lens, refocusing the light and therefore requiring less energy for lasing than was necessary in the cylinder experiment. Best of all, the cells survived the lasing process, and were able to produce hundreds of pulses of laser light.

A living laser could have a wide range of medical uses, according to lead author Malte Gather at the Wellman Center for Photomedicine at Mass. General. They could be used to activate drugs using light, for instance, or for new forms of imaging — it is difficult for visible and UV light to penetrate very far inside the body. Eventually, living lasers could enable optical communications and computing inside the body, using living systems instead of electronics.

Sourcs: Popsci,Eurekalert, BBC

Gemlike 3D microscope lens developed For 3D Microscopy

Engineers from Ohio State University have developed what they say is the world's first microscope lens capable of obtaining three-dimensional images. While 3D microscopy has already been achieved, it has previously required the use of multiple lenses, or of a single camera that moves around the object being imaged. The new device, however, is just a single lens that sits in place on an existing microscope.

The prototype lens was cut from a transparent piece of polymethyl methacrylate thermoplastic, also known as acrylic glass, using a commercially available milling tool outfitted with a diamond blade. The finished product, which is about the size of a fingernail, looks not unlike a gemstone. One side has a central facet circled by eight other facets, while the other side is flat. Unlike a gemstone, however, the facets are not intended to be identical – each one differs very slightly from the others in size and angle, which is an example of what is known as "freeform optics."

The lens was attached to a camera-equipped microscope, which looked down through the faceted side, to objects placed underneath. The nine facets each captured their own images of the objects, from slightly different angles. Those nine images were then fed to a computer, which combined them into one three-dimensional image. Objects that were observed included the tip of a ballpoint pen, with a diameter of about 1 millimeter, and a micro drill bit, with a diameter of just 0.2 mm.

It is hoped that once commercialized, the lens could be used in the manufacturing of microelectronics and medical devices, for medical testing, and to replace more complex machine vision systems. Although the prototype was machine milled, the engineers state that subsequent lenses could be less expensively produced via traditional molding techniques.

Allen Yi, associate professor of integrated systems engineering at Ohio State, and postdoctoral researcher Lei Li led the research. Their findings were recently published in the Journal of the Optical Society of America A.

Source: Gizmag

New microscope produces 3D movies of live cells in action

It's been a big week for the world of the small. In a new microscope breakthrough, researchers have figured out how to use a minuscule sheet of light to produce movies of living cells, revealing mitosis in action and illuminating cells' three-dimensional architecture with the greatest detail ever seen.

The technique uses a highly focused, super-thin beam of light similar to the type used in supermarket checkout scanners. It could allow cell biologists to watch the molecular underpinnings of cell action as they unfold.

"In looking at living systems, you want to be God. You want to have this omniscient power and be able to look at all time scales - not just single cells sitting on a microscope cover slip, but observe what's happening in a single molecule in a single cell that is inside your heart right now. That's the dream," said Eric Betzig, research leader at the Janelia Farm Research Campus, part of the Howard Hughes Medical Institute. "You want to have this (omniscience) in a way that the organism is completely unaware and unaffected by that observation."

The new technique, called Bessel beam plane illumination microscopy, could be the best way to do that without harming the cells.

In the past few months, other microscopy advances have allowed scientists to see 3-D structures of cells for the first time. MIT researchers are combining atomic force microscopywith magnetic resonance imaging to unveil 3-D images, for instance. A stochastic optical microscope under development at the University of Massachusetts uses a fluorescent tagging technique (which Betzig has also studied) to create mosaic images. And just this week, scientists in the UK announced a new technique that amplifies optical observations to seebeyond the diffraction limit of light, allowing cell and virus observations.

These are all promising techniques, but they're equivalent to taking a snapshot. When you are trying to understand complex processes, a snapshot is only worth so much - ideally, you would capture a live-action movie. It's more useful to watch the process of chromosomes pulling apart during cell division, like in the following video, or to see the ruffling of cell membranes, seen further below.

A movie would require observing a cell for a long time, but that causes some problems. If cells are not killed for the purposes of observing them, the process of lengthy observation does them in. One commonly used technique, confocal microscopy, uses a pinhole method to block out-of-focus light, allowing observations of very precise regions in the microscope's focal plane. But the whole specimen is still blasted with light, Betzig said.

"You can't study cells for too long before they literally curl up and die," he said. "And you can't study them very fast, because you have to scan them with a little point of light." The images are distorted, too, he said.

Betzig was looking for ways to overcome these problems, and started studying plane illumination, or shining light at a subject from the side rather than from below, like most microscopes. A European group developed a plane illumination microscope in 2003, and used it to show the development of an embryo as cells continually divided.

"They work very well when you are looking at embryos, which are hundreds of micrometers in diameter," Betzig said. "But they're not so great if you want to peer inside the guts of what is happening in each cell, which is what I wanted to do."

His research group decided to use a special focused beam called a Bessel beam, which does not diffract over long distances the way that regular light beams do. To keep the light super-focused, they had to modulate the beam, turning it on and off as it sweeps across the sample. The result is a series of high-speed images, which can be put together into a movie.

"We can study cells in their 3-D complexity at very high speeds for long periods of time. It's the combination of high axial resolution, plus high speed, plus the non-invasiveness that makes it special," Betzig said.

The wriggling mitochondria in this video represents 300 image stacks, each containing 300 two-dimensional images, taken in one second.

"That's almost 100,000 images of a cell, without bleaching it or harming it," Betzig said. "In in a second, can create an entire 3-D picture of what went on in that cell in that last second."

The next step could be combining the Bessel beam plane technique with super-resolution techniques, Betzig said. That would be something - with no limits on how small we can see, and an imaging technique that take movies without harming organisms, the possibilities seem endless.

Top Image: Three-dimensional structure of a fixed monkey kidney cell expressing the cancer signaling protein c-Src, showing membrane ruffles and numerous intracellular vacuoles. E. Betzig, T. Planchon, and L. Gao/Janelia Farm, Howard Hughes Medical Institute


Source:  Popular Science.