In the news today.
HILLSBORO, Ore. - Research conducted at Oregon Health & Science
University's Vaccine and Gene Therapy Institute (VGTI) has developed a
vaccine candidate in non-human primates that may eventually lead to a
vaccine against Human Immunodeficiency Virus (HIV). Details of this
advance are published in the advance online edition of the journal Nature.
The paper will also be published in an upcoming print addition of the
The research team, led by Louis Picker, M.D., associate director of the
OHSU VGTI and director of the VGTI¹s vaccine program, produced a vaccine
candidate that programs the immune system of non-human primates to respond
more swiftly to the presence of a primate version of HIV than it normally
would. The team also included researchers from the National Cancer
Institute-Frederick and the International AIDS Vaccine Initiative.
The VGTI researchers tested their vaccine candidate in rhesus macaque
monkeys at the Oregon National Primate Research Center using a monkey form
of HIV called Simian Immunodeficiency Virus (SIV). Of the monkeys that
received the vaccine candidate, just more than half controlled replication
of the virus to the extent that even the most sensitive tests could not
detect signs of SIV.
To date, the vast majority of these animals have maintained control over
the virus for more than a year, gradually losing any signs that they had
ever been infected. In contrast, the macaques in the unvaccinated control
group developed the monkey form of AIDS.
The researchers say that their work suggests that the immune responses
elicited by this new vaccine candidate might completely clear SIV from
animals that were initially infected. In comparison, antiretroviral
therapy is able to control the disease, but cannot clear the virus from
its hiding place within the immune systems own cells.
The VGTI team has been working for over ten years on its vaccine
candidate, which is unique in using Cytomegalovirus (CMV) as the transport
system used to introduce the vaccine into the body. CMV was chosen because
it is believed that most people are already infected with CMV, but for the
majority, the virus causes little or no symptoms. In addition, once a
person is infected with CMV, this virus remains in the body for life.
Picker and his team hypothesized that if such a persistent virus were used
as a vector it could create and maintain resistance against HIV by
programming a portion of the body¹s immune system called effector memory
T-cells to be constantly on the alert for the virus.
The next step in vaccine development is to test the vaccine candidate in
clinical trials in humans. For a human vaccine the CMV vector would be
weakened sufficiently so that it does not cause illness, but will still
protect against HIV, ² said Dr. Picker.
The National Institutes of Health and, the International AIDS Vaccine
Initiative provided funding for this research.