k*****e
发帖数: 22013 | 1 在猴子上的HIV同类SIV，已经研究出疫苗成功抑制感染。
方法是反过来，抑制免疫反应，把SIV当作自家人，不去攻击SIV，导致SIV无法感染免
疫细胞。
估计HIV的疫苗已经不远了。
Scientists have “unexpectedly” found a vaccine that completely blocks HIV
infection in monkeys
FIONA MACDONALD
FRIDAY, 29 AUGUST 2014
Human trials of the surprisingly simple vaccine are now planned. If
successful, it could be taken as a probiotic-like drink.
Image: Sebastian Kaulitzki/Shutterstock
A new oral vaccine has been found to completely stop rhesus macaque monkeys
from being infected with SIV, the monkey equivalent of HIV. The vaccine also
reduced the number of SIV particles that were present in monkeys who were
already infected with SIV.
The international research team, involving scientists from the Paris-
Descartes University in France and the University of Chinese Medicine in
Guangzhou, China, described the success of the vaccine as “surprising” and
“unexpected”, mainly because it's so simple.
The new vaccine works in the opposite way to most vaccines - by suppressing,
rather than triggering, an immune response. This is because HIV and SIV
actually require immune cells known asCD4 T-cellsin order to proliferate and
establish an infection in the body.
So one of the goals in HIV prevention has been to develop a vaccine that
introduces the body to the virus without causing an immune response. This
requires the vaccine to somehow trick the body into thinking HIV is harmless
, causing an ‘immune tolerance’ to the virus.
The scientists have now managed to do just that in monkeys, and their
results arepublished inFrontiers in Immunology.
The new vaccine works by stimulating the production of a previously unknown
group of immune cells known as CD8 T-cells, which then stop the monkeys’
CD4 cells from recognising SIV. This prevents any immune response and stops
SIV from hijacking the CD4 cells and spreading around the body.
The vaccine works because it's made up of inactivated SIV, but, importantly,
it’s given alongside doses of bacteria that are familiar to the body and
are recognised as ‘friendly’ - in this case, strains used in probiotics.
The researchers tested variations of the vaccine, involving different
bacteria strains, in 29 rhesus macaques - they were either given it as a
vaginal gel, a rectal douche, an oral vaccine or an oral probiotic-type
drink.
So far all 15 monkeys given the vaccine orally have been completely
protected against SIV infection, with the vaccinated monkeys still able to
suppress viral reproduction four years after vaccination.
The results are extremely positive, but the researchers admit they’re still
mystified as to why something as simple as giving inactivated SIV alongside
what is essentially a probiotic preparation produces such a strong immune-
suppressing result. When inactive SIV is given alone, it stimulates the
immune system as normal vaccines would.
Either way, the researchers are now looking into whether the same approach
would work in humans. Of course, SIV isn’t identical to HIV, and previously
vaccines that have looked extremely promising in animals studies have
failed to work in humans, so it’s important to keep these results in
perspective.
Two initial safety trials are now planned in humans both in HIV-negative and
HIV-positive volunteers.
José Esparza, a HIV vaccine researcher and professor at the Institute of
Human Virology in Baltimore in the US, who wasn’t involved in the study,
commented in an accompanying article in Frontiers in Immunology: “Although
the number of monkeys is relatively small, the levels of protection are
impressive”. He admits there was some scepticism surrounding the team’s
work, because their approach was so unorthodox and appeared so simple, but
he believes more funding is needed for out of the box approaches such as
this one.
“The solution to the HIV vaccine challenge will require genius, which…is
characterised not only by originality and usefulness, but also by surprising
results,”said Esparza.
Source: aidsmap |
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