Current serotype of dengue virus in Singapore disguises itself to evade vaccines and therapeutics

June 23, 2020

Dengue infections are rising, even as public health authorities are battling to contain the spread of the coronavirus. Dengue virus serotype 2 (DENV2) had previously been the predominant serotype but DENV3 has re-emerged in Singapore after almost three decades. This means the Singapore population has lower immunity to DENV3 and, consequently, a large proportion of the population is susceptible to DENV3 infection.

So far, there are no highly protective vaccines or therapeutic agents that target DENV. This is due to the possibility that antibodies raised against any one of the four known serotypes (DENV1-4) may enhance disease severity when an individual is infected with a different serotype in a secondary infection. This suggests an effective vaccine has to be able to stimulate equally strong protective responses simultaneously against all four serotypes. Adding further complication to vaccine development is the fact that there are different virus strains within each serotype, and different strains can exhibit vastly different shapes, enabling them to escape detection by a host's immune system. The Duke-NUS team had previously discovered that the surface of the DENV2 can change from smooth to bumpy depending on host conditions.

"Previous structural work focused mostly on DENV2, and therefore the other serotypes that are equally important are not well studied," said Professor Sheemei Lok from the Duke-NUS' Emerging Infectious Diseases (EID) programme and corresponding author of this study. "In this study, we found that DENV3 can dramatically transform itself from a smooth, round particle to a club-shaped particle -- like golf clubs, which would help the virus to evade hosts' immune response, vaccines and therapeutics."

The team also found some strains capable of transforming into club-shaped particles in DENV1, DENV2 and zika, though these exist as a minority of the virus population. Nonetheless, this suggests that flaviviruses have the potential to turn themselves into a conformation that is vastly different from their original structure, which can make vaccines and therapeutics ineffective against them.

"While Singapore has seen a recent spike in dengue cases, annually this virus infects about 400 million people worldwide, with a high prevalence in tropical and sub-tropical regions. In line with Duke-NUS vision of transforming medicine, this study gives new direction to developing better therapies and vaccines to treat or prevent dengue infections, and contribute to public health outcomes," said Prof Patrick Casey, Senior Vice Dean for Research at Duke-NUS.

The team is currently studying more DENV3 clinical strains to determine if this structural transformation is common.
-end-


Duke-NUS Medical School

Related Immune Response Articles from Brightsurf:

Boosting chickens' own immune response could curb disease
Broiler chicken producers the world over are all too familiar with coccidiosis, a parasite-borne intestinal disease that stalls growth and winnows flocks.

Cells sacrifice themselves to boost immune response to viruses
Whether flu or coronavirus, it can take several days for the body to ramp up an effective response to a viral infection.

Children's immune response more effective against COVID-19
Children and adults exhibit distinct immune system responses to infection by the virus that causes COVID-19, a finding that helps explain why COVID-19 outcomes tend to be much worse in adults, researchers from Yale and Albert Einstein College of Medicine report Sept.

Which immune response could cause a vaccine against COVID-19?
Immune reactions caused by vaccination can help protect the organism, or sometimes may aggravate the condition.

Obesity may alter immune system response to COVID-19
Obesity may cause a hyperactive immune system response to COVID-19 infection that makes it difficult to fight off the virus, according to a new manuscript published in the Endocrine Society's journal, Endocrinology.

Immune response to Sars-Cov-2 following organ transplantation
Even patients with suppressed immune systems can achieve a strong immune response to Sars-Cov-2.

'Relaxed' T cells critical to immune response
Rice University researchers model the role of relaxation time as T cells bind to invaders or imposters, and how their ability to differentiate between the two triggers the body's immune system.

A novel mechanism that triggers a cellular immune response
Researchers at Baylor College of Medicine present comprehensive evidence that supports a novel trigger for a cell-mediated response and propose a mechanism for its action.

Platelets exacerbate immune response
Platelets not only play a key role in blood clotting, but can also significantly intensify inflammatory processes.

How to boost immune response to vaccines in older people
Identifying interventions that improve vaccine efficacy in older persons is vital to deliver healthy ageing for an ageing population.

Read More: Immune Response News and Immune Response Current Events
Brightsurf.com is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to Amazon.com.