Nav: Home

Common virus is 'less prone to mutation' giving hope for vaccine development

February 25, 2019

One of the commonest causes of congenital disability, the Human Cytomegalovirus (HCMV), is less prone to mutation than previously thought, a finding which could help develop a successful vaccine, UCL researchers have found.

HCMV, a DNA virus and type of herpes virus, is one of the world's most common and widespread human infections, affecting between 45% to 100% of the adult population, depending on age and geographic area. While generally asymptomatic, HCMV is a concern for pregnant women, their unborn babies and patients with a weakened immune system. However developing a vaccine has proved elusive.

Previous global research has shown that within a single individual HCMV has high genome (genetic) diversity, leading to theories that HCMV has a high mutation rate. Such a trait is normally seen in RNA viruses, such HIV or Hepatitis C, which in turn makes them hard to develop vaccines against.

Now using new viral genome sequencing, bioinformatic and modelling tools developed at UCL, researchers have analysed immunocompromised patient blood samples and shown HCMV is not mutating any more than other DNA viruses. Instead, the frequent occurrence of mixed-infections caused by genetically different HCMV strains leads to findings of high genome diversity within an individual.

The study, funded by the European Union, has been published in Proceedings of the National Academy of Sciences.

Lead author, Professor Judith Breuer (UCL Division on Infection & Immunity), said: "It has been claimed that HCMV is as diverse as the more error prone RNA viruses such as HIV and Hepatitis C Virus and this has led to a lot of confusion in the field.

"Using our novel genome sequencing and bioinformatics modelling approaches, we have shown that the apparently high HCMV diversity seen in some clinical samples is caused not by HCMV mutation rather it is due to frequent co-infection with multiple strains of HCMV.

"Our study confirms for the first time that HCMV mutation rates are similar to other DNA viruses, providing some reassurance for the development of vaccines, as unlike the hyperdiverse RNA viruses, HCMV is unlikely to mutate to evade vaccines."

New UCL sequencing tool

Professor Breuer's work focuses on the application of next generation deep genome sequencing, helping uncover new virus characteristics.

The Breuer Lab has pioneered whole pathogen genome sequencing, by methods called 'targeted enrichment', to generate high quality whole viral genomes directly from clinical material, without the need for viral culture or polymerase chain reaction (PCR). She has combined these methods with cutting-edge bioinformatics including the newly developed Haplotype Reconstruction of Longitudinal Sequence Data (HaRoLD).

Developed at UCL, HaRoLD is a new computational tool that applies Bayesian mixture models to reconstruct the genome sequence of each individual virus present in a sample containing multiple viruses.

"This process is comparable to sorting several jigsaw puzzles that have been jumbled up together," added Professor Breuer.

"The new bioinformatics methods for re-constructing individual genome sequences from a mixed infection will allow us to identify the factors, including recombination, that drive HCMV evolution in a patient, providing a precision approach to managing infections."
-end-


University College London

Related Genome Sequencing Articles:

Rare feline genetic disorders identified through whole genome sequencing at MU
In 2009, Joan Coates, a veterinary neurologist, along with other researchers at the University of Missouri and the Broad Institute, found a genetic link between degenerative myelopathy (DM) in dogs and amyotrophic lateral sclerosis (ALS), or Lou Gehrig's disease in people.
With cancer genome sequencing, be your own control
University of Colorado Cancer Center study shows that mapping cancer cells to published reference genomes is less accurate than mapping them to genomes of healthy cells from same subject.
Genome sequencing reveals ancient interbreeding between chimpanzees and bonobos
For the first time, scientists have revealed ancient gene mixing between chimpanzees and bonobos, mankind's closest relatives, showing parallels with Neanderthal mixing in human ancestry.
Genome sequencing helps determine end of tuberculosis outbreak
Using genome sequencing, researchers from the University of British Columbia, along with colleagues at the Imperial College in London, now have the ability to determine when a tuberculosis outbreak is over.
How did the giraffe get its long neck? Clues now revealed by new genome sequencing
For the first time, the genomes of the giraffe and its closest living relative, the reclusive okapi of the African rainforest, have been sequenced -- revealing the first clues about the genetic changes that led to the evolution of the giraffe's exceptionally long neck and its record-holding ranking as the world's tallest land species.
Interpreting clinical sequencing results for genome medicine
Medical geneticist Robert C. Green and clinical molecular geneticist Heidi Rehm are available to discuss the best path forward for interpreting results from clinical genome and exome sequencing.
Successful precision medicine will require more accurate genome sequencing
Large areas of medically important genes fall within troublesome regions of the human genome, where it is currently difficult to obtain accurate sequence information, according to research published in the open access journal Genome Medicine.
New software provides an overview of the big data of genome sequencing
Since researchers first succeeded in mapping the human genome back in 2003, the technological development has moved at warp speed, and the process which at that time took several years and billions of dollars can now be performed in a few days.
Sequencing algae's genome may aid biofuel production
University of Washington scientists have sequenced the complete genetic makeup of a species of ecologically important algae, which may aid in biofuel production.
Whole genome-sequencing uncovers new genetic cause for osteoporosis
Using one of the world's most extensive genetics data sets, an international research team led by Dr.

Related Genome Sequencing Reading:

Best Science Podcasts 2019

We have hand picked the best science podcasts for 2019. Sit back and enjoy new science podcasts updated daily from your favorite science news services and scientists.
Now Playing: TED Radio Hour

Digital Manipulation
Technology has reshaped our lives in amazing ways. But at what cost? This hour, TED speakers reveal how what we see, read, believe — even how we vote — can be manipulated by the technology we use. Guests include journalist Carole Cadwalladr, consumer advocate Finn Myrstad, writer and marketing professor Scott Galloway, behavioral designer Nir Eyal, and computer graphics researcher Doug Roble.
Now Playing: Science for the People

#530 Why Aren't We Dead Yet?
We only notice our immune systems when they aren't working properly, or when they're under attack. How does our immune system understand what bits of us are us, and what bits are invading germs and viruses? How different are human immune systems from the immune systems of other creatures? And is the immune system so often the target of sketchy medical advice? Those questions and more, this week in our conversation with author Idan Ben-Barak about his book "Why Aren't We Dead Yet?: The Survivor’s Guide to the Immune System".