Fact Sheet February 2005
HIV: A Worldwide Pandemic
The following statistics come from the World Health Organization:
-
Acquired immunodeficiency syndrome (AIDS) has claimed nearly 30 million lives worldwide; more than 14 million children have lost one or both parents to AIDS, the late stage of infection with human immunodeficiency virus (HIV).
-
AIDS kills more than 8,000 people every day; one person every 10 seconds dies of AIDS.
-
Nearly 40 million adults and children are infected with HIV.
-
Nearly 5 million additional people (4.3 million adults and 700,000 children) are infected with HIV each year.
What Makes HIV Unique?
-
HIV attacks the body by rapidly replicating inside immune cells, the cells that normally help protect against infection. Signals that activate these immune cells to fight infection also activate HIV, stopping the immune response and spreading the virus.
-
HIV rapidly mutates to create versions of the virus that escape recognition by the carrier’s immune system.
-
HIV mutates so rapidly that that every person infected with the virus carries a different strain.
New Approaches to HIV Vaccine Design
-
Researchers seek a vaccine that induces the cellular arm of the immune system to help protect against the HIV infection. A cellular vaccine trains the immune system to recognize short fragments of foreign protein called epitopes that are found on the surface of infected cells. Once recognized, the immune system kills the infected cell.
-
Researchers at Royal Perth Hospital in Australia are attempting to locate genetic patterns in the way HIV mutates to evade different human leukocyte antigen (HLA) immune types. By uncovering the characteristic ways the virus mutates to avoid recognition, the researchers hope to determine the HIV epitopes that must be included in a vaccine to train an infected person’s body to fight a myriad of HIV strains.
-
University of Washington researchers are tracing the genetic family tree of the virus back to the earliest strains of the virus. By including these “ancestral” epitopes in a vaccine, the researchers hope to provide the immune system with the epitopes necessary to recognize all strains of the virus.
Microsoft Research Contributions to Vaccine Models
The Microsoft Research Machine Learning and Applied Statistics Group developed the following resources:
-
Machine-learning and data-mining algorithms that for the first time allow researchers to utilize the patterns found by the Royal Perth Hospital to locate new epitopes. The algorithms combed through hundreds of genetic sequences to find epitopes more efficiently than did previous methods. Similar Microsoft algorithms are used in Microsoft®
products to analyze large computer databases and to separate spam from legitimate e-mail. -
Algorithmic models, or epitomes, that for the first time allow medical researchers to compress multiple HIV epitopes into a vaccine of manageable size. The epitomes reduce the size by overlapping the epitopes, while providing the immune system with the genetic information it needs to fight off different strains of the virus. Vaccine candidates that use this approach are less than half as long as ones in which the epitopes don’t overlap. By reducing the size and genetic components, the vaccines are easier to administer and less costly to create. Microsoft Research developed similar epitomes to summarize diversity in images, video and audio signals.
Current Status and Next Steps
-
Laboratory tests of the HIV vaccine models on samples of HIV-infected cells began in February 2005. Initial results should be available later in 2005.
-
If the models succeed, Microsoft Corp. will do algorithmic analysis to determine if the multiple epitopes reduce the effectiveness of the vaccines, a phenomenon called immunodominance.
-
Microsoft and HIV researchers plan to work with colleagues in other areas of vaccine research to see if the computer-enhanced vaccine models can be applied to the development of treatments for hepatitis C and other mutating viruses.
Microsoft is a registered trademark of Microsoft Corp. in the United States and/or other countries.
The names of actual companies and products mentioned herein may be the trademarks of their respective owners.