In the Emory study, the researchers, using computer simulations, developed an experimental design in which animals are repeatedly exposed to low doses of HIV (similar to how humans are exposed and infected). The belief that experiments involving realistically low challenge doses would require large numbers of animals has so far prevented the development of such trials, the researchers say.

Through computer simulations and statistical analysis of their virtual experiments, the Emory researchers showed that such trials would require far fewer animals than previously thought. Their research will be published in the July 19 issue of the Public Library of Science Medicine. A press-only preview of the article can be found at http://www.plos.org/press/plme-02-08-regoes.pdf.

"We demonstrate that using low doses and challenging repeatedly -- which also is more realistic because humans are typically exposed repeatedly to HIV -- represents a very promising design," says Roland Regoes, a postdoctoral researcher in Emory's biology department and lead author of the study.

Trials in animal models have long played an essential role in evaluating the effectiveness of potential HIV vaccines and treatments. When assessing vaccine efficacy in animal models, the animals are first given the potential vaccination. They are then "challenged" (or infected) with the virus or pathogen against which the vaccine should give protection. In simian models of HIV infection, Simian Immunodeficiency Virus (SIV), closely related to HIV, is used to challenge macaques. The trials are usually conducted with very high challenge doses of
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Contact: Beverly Cox Clark
beverly.clark@emory.edu
404-712-8780
Emory University Health Sciences Center
20-Jul-2005