(Editor's Note: Scientist Live is launching a new, interactive feature, The Scientist Audio Mailbag. Here's how it works: Each week, we select a current news item and then arrange an interview with the researcher involved in the study. Scientist Live readers will be allowed to mail in questions to be presented to the scientist. The editors will then select a handful and pose them to the researcher. You will be able to hear their answers in their own words. Our first Mailbag deals with a promising new anti-HIV gel. Join the discussion now.)
New research at Oregon Health & Science University's Vaccine and Gene Therapy Institute suggests vaccines that specifically target HIV in the initial stages of infection before it becomes a rapidly replicating, system-wide infection - may be a successful approach in limiting the spread of the disease. The research is published in the early online edition of the journal Nature Medicine and will appear in a future printed edition.The researchers used a vaccination method that involves creating and maintaining resistance by programming a portion of the body's immune system - effector memory T-cells - to look out for HIV at the site of infection.
"HIV appears to be vulnerable when it is first introduced into mucosal surfaces in the body," said Louis Picker, M.D., associate director of the OHSU VGTI and director of the VGTI's vaccine program. "However, once HIV spreads throughout the entire body, it replicates very rapidly and becomes difficult if not impossible to control. Our approach is to attack during this early period of vulnerability. The approach is similar to that of a homeowner who sprays their house with water before sparks land on the roof. This approach can prevent the roof from catching fire and, in the case of HIV, prevent the spread of the virus."
To determine whether they could proactively "educate" the immune system, scientists used a monkey model of AIDS - simian immunodeficiency virus (SIV) - the monkey counterpart to HIV. They introduced an altered monkey form of cytomegalovirus (CMV) programmed to express SIV proteins and trigger specialised effector memory T-cells to look for and attack SIV in its early stages.
In total, 12 rhesus macaque monkeys at the Oregon National Primate Research Center were vaccinated using this method. When the animals were later infected with SIV, one-third were protected.
The next step for the research team is to try to determine why only a portion of the monkeys who are vaccinated using this method are responding. The researchers also hope to expand the number of subjects to better determine the success rate of the therapy.
