A NEW compound has blocked Human
Immuno-deficiency Virus (HIV) infection
so well in monkeys that it may be able to
function as a vaccine against Acquired
Immune Deficiency Syndrome (AIDS), the
scientists who designed it reported
midweek. The study was published online
by the journal Nature.
Meanwhile, the Nigerian Veterinary
Medical Association (NVMA) yesterday
issued concerns over the Highly
Pathogenic Avian Influenza (HPAI)
resurgence in the country.
While the association is optimistic that
if Nigeria works together as a nation, it
could conquer the disease like the Ebola
Virus Disease; it also called on all
veterinary doctors to consider the
resurgence of the disease, also known as
Bird Flu, as a professional challenge and
should quickly rise to the occasion.
HIV has defied more than 30 years of
conventional efforts to fashion a vaccine.
The new method stimulates muscle cells
to produce proteins that somewhat
resemble normal antibodies, which have
Y-shaped heads. These proteins have
both a head and a tail, and they use them
to simultaneously block two sites on each
“spike” that the virus uses to attach itself
to a cell.
If both sites can be blocked on every
spike, the virus becomes helpless and
drifts off unattached into eventual oblivion
by the immune system.
Director of the National Institute of
Allergy and Infectious Diseases (NIAID)
United States, which supported the work,
Dr. Anthony S. Fauci, said: “It’s a twofer.
It’s very impressive, and the method is
quite promising. But it’s still just in an
animal model, so we’ll need to see
evidence of whether it works in humans.”
The technique, the paper’s lead author
said, had completely protected four
monkeys for nearly a year against
repeated attempts to infect them with large
doses of several strains of SHIV, a version
of HIV adapted for use in lab monkeys.
The author, Michael Farzan, an infectious
disease specialist at the Scripps Research
Institute in Florida, described the new
compound as “the broadest and most
potent entry inhibitor described so far.”
It is simpler and works better, he said,
than the current method that scientists are
experimenting with: giving monkeys
cocktails of several different antibodies
that each neutralise only one or two
strains of HIV, sometimes imperfectly.
Describing over the telephone the way
his new compound worked, Farzan said
that he was bending his hand into a claw,
with his thumb representing the end
blocking one site and two fingers blocking
the other.
“One of my colleagues told me it’s the
grip for a two-seam cut fastball,” he said.
The work was led by scientists at his
institute but involved researchers from
Harvard, Princeton, Rockefeller University,
the University of Southern California, the
Pasteur Institute in France and elsewhere.
The next step, Farzan said, would be to
test the compound in infected monkeys
and see if it could stop the virus from
replicating further, which is what
antiretroviral medicines do. If that proves
safe and effective, he said, he hoped to
start human trials in three stages.
In the first, humans would be injected
every few weeks with just the antibody-
like protein, not with the vector that
stimulates muscle cells to produce it. If
that were successful, the vector would be
injected into humans who already have
HIV, but are not taking antiretroviral pills
because they refuse, forget or experience
bad side effects.
Finally, the compound would be given to
healthy people at high risk – such as gay
men who have frequent unprotected sex
with strangers – to see if it protects them.
The new approach uses cutting-edge
techniques that are not widely known, or
even entirely understood, by the scientists
experimenting with them.
Historically, vaccines have been made by
killing or weakening whole viruses and
injecting them; that stimulates the
immune system to produce antibodies
that recognise and attack the real virus
when it arrives.
Newer vaccines splice genes for
particular antibodies into other weakened
viruses. Generally, the genes are carried
into a cell by the virus, incorporated into
the cell’s genome, and begin producing
the necessary antibodies.
But this new method splices the desired
gene into a stretch of DNA so short that it
cannot function like a virus at all and does
not deserve to be called one, Farzan said,
who referred to it simply as “a gene
therapy vector.” It does not integrate itself
into the DNA of a cell or replicate itself.
Nonetheless, injecting that vector into
muscle stimulates cells to produce the
antibody-like protein encoded by the
gene.
“Why? We’re not really able to answer
that question,” Farzan said. “But it does.”
HIV normally targets CD4 cells, white
blood cells that act as the sentinels of the
immune system.
The virus invades them by attaching its
outer spikes – known as envelope
proteins – to two different receptors on
the outside of the cell. First it attaches to
the CD4 receptor; that exposes the CCR5
receptor. Once attached to both, the virus
can inject its RNA into the cell and hijack
its inner machinery to produce more
viruses.
But the protein produced by Farzan, bent
into its claw shape, blocks both the CD4-
binding site and the CCR5-binding site. It
does so in a very tight “match” difficult for
the virus to block by means of “escape
mutations” – changes in shape that partly
prevent engineered antibodies from
attaching.
“It fools the virus into thinking it’s
interacting with a cell,” Farzan said.
Dr. Philip R. Johnson, director of the
Children’s Hospital of Philadelphia
Research Institute and the inventor of the
vector that Farzan used, called the new
approach “good stuff.”
“It appears to be as good as, if not
better than, anything else that’s being
tried,” he said.
Eventually, he said, he would like to see
an approach that combined known
antibodies and the new protein “so we
could target two or three areas on the
virus.”
In a chat with journalists in Abuja,
National President of the Association, Dr.
Edgar Amos Sunday, also called for the
review and streamlining of the Animal
Disease (Control) Decree of 1988 to suite
contemporary realities.
Measures to check spread
The NVMA further stressed that poultry
meat and eggs should be hygienically
processed, noted that if well-cooked, is
safe for human consumption.
The body also weighed the scientific and
other arguments concerning the use of
vaccines for Bird Flu and suggested that
government’s current policy against
vaccination as a strategy in the control of
bird flu should be sustained.
Sunday urged the public not to panic,
but called on poultry farms to ensure strict
monitoring and restriction of movement of
people and items such as crates, bags
and so on, especially between farms. The
association also canvassed strict hygiene
before and after handling poultry.
He added: “Cases of ill health in poultry
should be reported immediately to the
nearest veterinary clinic.
“The Avian Influenza Control Project
structures in various states should be
strengthened and equipped to carry out
public enlightenment, surveillance,
depopulation, disinfection and so on. State
governments in particular should invest
more in providing and upgrading
veterinary infrastructure. Active
surveillance should be carried out
immediately throughout the country even
in states where the disease has not been
reported. This is to facilitate movement
ahead of the virus.
“More veterinary doctors should be
employed by government. The situation in
some states that have less than 10
veterinary doctors in their service is
inimical to both animal and public health.
Such states cannot effectively deliver
health service and control of diseases like
bird flu.”
He further stressed: “More veterinary
hospitals, clinics and laboratories should
be constructed while existing ones should
be rehabilitated and equipped. Specifically,
the National Veterinary Research Institute
(NVRI) laboratory in Vom and its branches
should be supported to enhance the
capacity for quick and accurate diagnosis
of bird flu and other diseases.
Development partners should lend their
support in these regard.
“Standard operational procedures for
poultry business should be re-designed
and implemented.”
He called on government to provide
sufficient funds for the payment of
compensation to farmers whose poultry
had been depopulated.
Current situation
Sunday disclosed: “The current outbreak
was first reported from a commercial farm
in Kano on December 24, 2014 and a live
bird market at Onipanu in Lagos on
January 8, 2015. This was confirmed by
the NVRI, Vom. As at February 18, the
disease had been confirmed in 17 states
nationwide. These are Kano, Lagos, Ogun,
Rivers, Delta, Plateau, Edo, Gombe, Imo,
Oyo, Jigawa, Kaduna, Bauchi, Zamfara,
Katsina, Sokoto and Anambra.
“The confirmed cases are from 146
poultry farms, 10 live bird markets and 11
zoological gardens spread in 61 local
government areas. There has not been
any reported case of bird flu so far in
humans in the country and all human
samples have so far tested negative.”
He stressed, however, that the prospects
for containment were bright despite the
implications of bird resurgence in Nigeria
“The experience, technical manpower,
facilities and support used in containing
the 2006 outbreak is accessible,” he
added.

http://m.ngrguardiannews.com/en/news/national-news/198871-new-approach-to-blocking-hiv-raises-hopes-for-aids-vaccine

Nice