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Computer Models Aid Understanding Of Antibody-dependent Enhancement In Spread Of Dengue Fever

Date:
October 15, 2005
Source:
Johns Hopkins University Bloomberg School of Public Health
Summary:
Some viruses' ability to exploit the human body's own defenses to increase their replication may be both a blessing and curse, according to the findings of a study. Scientists believe antibody-dependent enhancement may allow the dengue virus to grow more rapidly in people who were previously infected and have partial but incomplete immunity to the virus. The findings could one day lead to new strategies for developing and deploying vaccines.
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Some viruses’ ability to exploit the human body’s owndefenses to increase their replication may be both a blessing andcurse, according to the findings of a study conducted by researchers atthe Johns Hopkins Bloomberg School of Public Health. The process isknown as antibody-dependent enhancement. Scientists believeantibody-dependent enhancement may allow the dengue virus to grow morerapidly in people who were previously infected and have partial butincomplete immunity to the virus. Enhanced virus replication triggers amore deadly, hemorrhagic form of the disease. A study published in theonline edition of Proceedings of the National Academy of Sciencessuggests that antibody-dependent enhancement offers an evolutionarytrade-off between advantage and disadvantage for the dengue virus. Thefindings could one day lead to new strategies for developing anddeploying vaccines.

Using computational models based on epidemictheory, the researchers examined the dynamic role antibody-dependentenhancement plays in the spread of dengue viruses. They concluded thatwhen antibody-dependent enhancement triggered small increases intransmission it gave viruses an edge over other co-circulating dengueviruses that did not experience enhancement. Counter-intuitively,larger increases in transmission resulted in more extinctions of theenhanced virus.

“Dengue dynamics are similar to predator-preysystems in ecology. Antibody-dependent enhancement makes a virus abetter predator. But there comes a point where the predator gets sogood it runs out of prey,” explained lead author Derek Cummings, aresearch associate in the Department of International Health at theBloomberg School. “We found that antibody-dependent enhancement helpsthe dengue virus spread faster, but there are limits to how much thevirus can exploit this strategy.”

According to the computersimulations, antibody-dependent enhancement creates oscillations, or“booms and busts” in the incidence of dengue virus infections.Enhancement results in larger booms, but also deeper troughs inincidence, which lead to extinction. Although the computer models werespecifically developed for dengue, the researchers believe the resultscould apply to any disease in which partial immunity increases pathogenreplication rates.

“Experimental dengue vaccines will soon beentering into large-scale clinical trials. We must understand theprocesses that affect transmission—such as antibody-dependentenhancement—to design optimal dengue vaccination strategies,” saidDonald S. Burke, MD, senior author of the study and professor in theDepartment of International Health at the Bloomberg School.

“Dynamiceffects of antibody-dependent enhancement on the fitness of viruses”was written by Derek A. T. Cummings, Ira B. Schwartz, Lora Billings,Leah B. Shaw and Donald S. Burke. Cummings and Burke are with the JohnsHopkins Bloomberg School of Public Health. Schwartz and Shaw are withthe Naval Research Laboratory, Washington, D.C., and Billings is withMontclair State University.

Funding was provided by grants fromthe National Institute of General Medical Sciences of the NationalInstitutes of Health, the National Oceanic and AtmosphericAdministration, the Environmental Protection Agency, the NationalAeronautics and Space Administration, the National Science Foundation,the Office of Naval Research and the Center for Army Analysis and theNational Research Council.


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Materials provided by Johns Hopkins University Bloomberg School of Public Health. Note: Content may be edited for style and length.


Cite This Page:

Johns Hopkins University Bloomberg School of Public Health. "Computer Models Aid Understanding Of Antibody-dependent Enhancement In Spread Of Dengue Fever." ScienceDaily. ScienceDaily, 15 October 2005. <www.sciencedaily.com/releases/2005/10/051015092305.htm>.
Johns Hopkins University Bloomberg School of Public Health. (2005, October 15). Computer Models Aid Understanding Of Antibody-dependent Enhancement In Spread Of Dengue Fever. ScienceDaily. Retrieved November 9, 2024 from www.sciencedaily.com/releases/2005/10/051015092305.htm
Johns Hopkins University Bloomberg School of Public Health. "Computer Models Aid Understanding Of Antibody-dependent Enhancement In Spread Of Dengue Fever." ScienceDaily. www.sciencedaily.com/releases/2005/10/051015092305.htm (accessed November 9, 2024).

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