In the last month, UCLA researchers have published two studies
that contribute to the search for both the prevention and treatment
of AIDS.
A group of researchers from the UCLA AIDS Institute and the Los
Alamos National Laboratory published a study exploring why some
mothers with HIV-1 transfer the virus to their babies through the
uterus while others do not, leading them closer to finding a
vaccine for HIV.
Meanwhile, researchers from the AIDS Institute and the Institute
for Stem Cell Biology and Medicine showed for the first time that
human embryonic stem cells can be formed into human T-cells, giving
momentum to a gene therapy approach to fighting AIDS.
AIDS is caused by the damage of the immune system by the human
immunodeficiency virus (HIV) and has killed 25 million people
worldwide since the virus was first recognized in the early 1980s,
according to the Joint United Nations Programme on AIDS.
Though treatment can slow the effects of the virus, there is
currently no cure.
As a part of the 10-year study examining virus transfer between
mothers and babies, UCLA researchers studied 38 randomly selected
infant-mother pairs and found that mothers who had the maternal
autologous neutralizing antibody (aNAB) were significantly less
likely to transmit HIV-1 to their babies.
Antibodies are large, Y-shaped proteins used by the immune
system to identify and neutralize foreign objects like bacteria and
viruses. Researchers determined that a mother who has aNAB
transfers the antibody through the placenta into the fetal
bloodstream and therefore to the fetus, naturally vaccinating the
child against HIV-1.
“This is the first study that shows that antibody is
important in transmission from mother to child, and it also shows
that if HIV-1 is transmitted, the strain of the virus transmitted
to the infant is the same strain that was resistant to antibody in
the mother,” said Dr. Yvonne Bryson, chief of pediatric
infectious diseases at the Mattel Children’s Hospital at UCLA
and an author of the study.
The study’s results suggest that the antibody has a
selective or protective effect on HIV-1 transmission.
“I think it is an important discovery because a
neutralizing antibody is important for the future of a vaccine
against HIV,” said Bryson.
Researchers around the world have worked for decades to find a
vaccine for AIDS, believing it is the only option that can
ultimately end the epidemic.
“The vaccine could be used on infants, young adolescents,
anyone who is at risk. This technology could potentially stop the
epidemic,” said Bryson.
The second group of UCLA researchers approached the AIDS problem
from a different angle, working to develop a system of cell
replacement and gene therapy that could counter the disease in case
an effective vaccine ultimately proves unattainable.
UCLA researchers coaxed human embryonic stem cells into T-cells,
which regulate immune response and are the main target of the HIV
virus.
“Human embryonic stem cells are obtained from the cells of
an early-stage human embryo and mature to make all the organisms
and tissues of the human body,” said Dr. Jerome Zack,
professor of medicine and of microbiology, immunology and molecular
genetics at the David Geffen School of Medicine at UCLA and author
of the study.
Researchers developed blood stem cells from human embryonic stem
cells in petri dishes and then injected the blood cells into a
human thymus they had implanted in a mouse.
The thymus, an organ located above the heart, where T-cells
traditionally develop, turned the human blood cells into human
T-cells.
“People have worked with mouse embryonic stem cells for 20
to 30 years, but using human embryonic stem cells is completely
new,” said Zoran Galic, professor in the department of
medicine, division of hematology and oncology and lead researcher
on the study.
“The ability to get human embryonic stem cells to form
T-cells is a holy grail in our field. This challenge had to be
surmounted before we could move forward in treating HIV,”
said Zack.
Researchers say the study is not important as an immediate
promise of an HIV treatment, but because it shows for the first
time that this technology is even possible.
Though both studies are years away from providing tangible
treatment to patients suffering from HIV, researchers believe they
are absolutely integral to the advancement of the fight against
AIDS.