Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Scientists engineer strain of MERS coronavirus for use in a vaccine

10.09.2013
Scientists have developed a strain of the Middle East respiratory syndrome coronavirus (MERS-CoV) that could be used as a vaccine against the disease, according to a study to be published in mBio®, the online open-access journal of the American Society for Microbiology.

The mutant MERS virus, rMERS-CoV-ΔE, has a mutation in its envelope protein that makes it capable of infecting a cell and replicating its genetic material, but deprives it of the ability to spread to other tissues and cause disease.

The authors say once additional safe guards are engineered into the virus, it could be used as the basis of a safe and effective live-attenuated vaccine against MERS.

"Our achievement was a combination of synthetic biology and genetic engineering," says co-author Luis Enjuanes of The Autonomous University of Madrid (Universidad Autónoma de Madrid).

"The injected vaccine will only replicate in a reduced number of cells and produce enough antigen to immunize the host," he says, and it cannot infect other people, even those in close contact with a vaccinated person.

Since MERS was first identified in June 2012, the World Health Organization has been notified of 108 cases of infection, including 50 deaths. Although the total number of cases is still relatively small, the case fatality rate and the spread of the virus to countries beyond the Middle East is alarming to public health officials. If the virus evolves the ability to transmit easily from person to person, a much more widespread epidemic is possible. Diagnostic assays and antiviral therapies for MERS have been described, but reliable vaccines have not yet been developed.

Enjuanes and his team applied what they had learned from 30 years of research on the molecular biology of coronaviruses to synthesize an infectious cDNA clone of the MERS-CoV genome based on a published sequence. They inserted the viral cDNA chromosome into a bacterial artificial chromosome, and mutated several of its genes, one by one, to study the effects on the virus' ability to infect, replicate, and re-infect cultured human cells.

Mutations that disabled accessory genes 3, 4a, 4b and 5 did not seem to hinder the virus: mutant viruses had similar growth rates as the wild-type virus, indicating that the mutations do not disable the virus enough to deploy the mutants in a vaccine. Mutations in the envelope protein (E protein), on the other hand, enabled the virus to replicate its genetic material, but prevented the virus from propagating, or infecting nearby cells.

A large amount of the rMERS-CoV-ΔE virus would be needed for a live attenuated MERS vaccine. A virus that can't propagate itself would be unable to grow the volume needed without help. Enjuanes says they provided the virus with a supplemental form E protein.

"To grow the virus, we create what are called 'packaging cells' that express the E protein missing in the virus. The gene to encode this protein is integrated in the cell chromosomes and will not mix with the viral genes. Therefore, in these cells, and only within them, the virus will grow by borrowing the E protein produced by the cell," says Enjuanes. "When the virus in administered to a person for vaccination, this person will not be able to provide the E protein to the defective virus," so the virus will die off after producing antigens to train the human immune system to fight a MERS-CoV infection.

Enjuanes says rMERS-CoV-ΔE is a very promising vaccine candidate, but more work remains before they can start clinical trials. He says the mutation in the E protein that prevents the virus from propagating represents one safe guard, but the US Food and Drug Administration requires that a recombinant live attenuated vaccine strains include at least three safe guards to ensure the virus doesn't revert easily back to its virulent form. His group is currently working on introducing other disabling mutations in genes that are located in regions of the virus' genome that are far away from the E protein gene to ensure the virus cannot revert back to virulence in a single recombination event.

mBio® is an open access online journal published by the American Society for Microbiology to make microbiology research broadly accessible. The focus of the journal is on rapid publication of cutting-edge research spanning the entire spectrum of microbiology and related fields. It can be found online at http://mbio.asm.org.

The American Society for Microbiology is the largest single life science society, composed of over 39,000 scientists and health professionals. ASM's mission is to advance the microbiological sciences as a vehicle for understanding life processes and to apply and communicate this knowledge for the improvement of health and environmental and economic well-being worldwide.

Jim Sliwa | EurekAlert!
Further information:
http://www.asmusa.org
http://mbio.asm.org

More articles from Life Sciences:

nachricht Single-stranded DNA and RNA origami go live
15.12.2017 | Wyss Institute for Biologically Inspired Engineering at Harvard

nachricht New antbird species discovered in Peru by LSU ornithologists
15.12.2017 | Louisiana State University

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: First-of-its-kind chemical oscillator offers new level of molecular control

DNA molecules that follow specific instructions could offer more precise molecular control of synthetic chemical systems, a discovery that opens the door for engineers to create molecular machines with new and complex behaviors.

Researchers have created chemical amplifiers and a chemical oscillator using a systematic method that has the potential to embed sophisticated circuit...

Im Focus: Long-lived storage of a photonic qubit for worldwide teleportation

MPQ scientists achieve long storage times for photonic quantum bits which break the lower bound for direct teleportation in a global quantum network.

Concerning the development of quantum memories for the realization of global quantum networks, scientists of the Quantum Dynamics Division led by Professor...

Im Focus: Electromagnetic water cloak eliminates drag and wake

Detailed calculations show water cloaks are feasible with today's technology

Researchers have developed a water cloaking concept based on electromagnetic forces that could eliminate an object's wake, greatly reducing its drag while...

Im Focus: Scientists channel graphene to understand filtration and ion transport into cells

Tiny pores at a cell's entryway act as miniature bouncers, letting in some electrically charged atoms--ions--but blocking others. Operating as exquisitely sensitive filters, these "ion channels" play a critical role in biological functions such as muscle contraction and the firing of brain cells.

To rapidly transport the right ions through the cell membrane, the tiny channels rely on a complex interplay between the ions and surrounding molecules,...

Im Focus: Towards data storage at the single molecule level

The miniaturization of the current technology of storage media is hindered by fundamental limits of quantum mechanics. A new approach consists in using so-called spin-crossover molecules as the smallest possible storage unit. Similar to normal hard drives, these special molecules can save information via their magnetic state. A research team from Kiel University has now managed to successfully place a new class of spin-crossover molecules onto a surface and to improve the molecule’s storage capacity. The storage density of conventional hard drives could therefore theoretically be increased by more than one hundred fold. The study has been published in the scientific journal Nano Letters.

Over the past few years, the building blocks of storage media have gotten ever smaller. But further miniaturization of the current technology is hindered by...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

See, understand and experience the work of the future

11.12.2017 | Event News

Innovative strategies to tackle parasitic worms

08.12.2017 | Event News

AKL’18: The opportunities and challenges of digitalization in the laser industry

07.12.2017 | Event News

 
Latest News

Engineers program tiny robots to move, think like insects

15.12.2017 | Power and Electrical Engineering

One in 5 materials chemistry papers may be wrong, study suggests

15.12.2017 | Materials Sciences

New antbird species discovered in Peru by LSU ornithologists

15.12.2017 | Life Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>