While main challenge was to develop a model which replicates practical situation where humans are exposed repeatedly to very low copies of HIV resulting in infection , Rajeev says that they are in process of testing long-acting versions of these antibodies to achieve an annual administration of monoclonal antibodies for full protection .
This kind of HIV Vaccine would be great for the under developed African countries as well as developing Asian nations where people can ' t afford expensive HIV-AIDS treatment . “ HIV is a number one killer among infectious diseases in African countries and rate of new HIV infections are consistently increasing in Asian countries . Without any doubt , vaccine is the need of an hour but HIV is very notorious as it changes itself very fast to escape any counter effect ,” he says while pointing towards the long road ahead .
More about the experiments and proof of concept
As per Rajeev , the majority of HIV infections are transmitted via mucosal route therefore repeated mucosal low dose challenge in Indian rhesus macaque was used to test the efficacy of antibodies .
They had examined " passive immunisation " as an alternative to an HIV vaccine , which experts fear may still be years off . A vaccine works by priming the body to respond with germ-fighting antibodies whenever a virus or bacteria invades . It is longlasting , sometimes for life .
" Passive immunisation " involves the transfer of antibodies generated by one person directly to another to provide protection , which is shorter in duration .
In the study , researchers used four powerful antibodies that are known for neutralizing several strains of HIV circulating around the world . The antibodies were produced by certain HIV-infected people and purified in a lab before being used in the study . The researchers injected four groups of macaques with a different antibody . A week after the monkeys were given the antibodies , they were exposed to weekly low doses of a monkey version of the HIV virus . ( The human version only infects people .) The antibodies were found to protect the macaques from becoming infected for 12 to 14 weeks on average . Some animals were even protected for as long as 23 weeks . For monkeys without the antibody , it took an average of three weeks to become infected with HIV .
How is it different ?
While the antibodies have already been used to delay HIV infection in macaques , in most of those studies , the monkeys were infected with HIV with a single high-dose shot of the virus . Whereas , in this study , the monkeys were instead exposed to the virus in low doses week by week , not all at once . That mimics the way that people get exposed to HIV in real life . In fact , people usually don ’ t get infected with HIV the first time they ’ re exposed to the virus .
While the preventive HIV medications already exist , but they still can ’ t give the completely desired results . Pills like
“
PrEP , for example , reduce the risk of getting infected from sex by more than 90 percent . The problem is that these need to be taken daily , and people often forget or they run out of pills or they take the medication only when they have sex . And that reduces the drug ’ s effectiveness . This is why scientists are looking for other medications that can prevent HIV infections .
Way forward
We found that enough concentration of monoclonal antibodies stays in body for long time and blocks infection when repeatedly exposed to HIV .
DR RAJEEV GAUTAM With over 14 years of research experience , Dr Rajeev Gautam holds PhD in bacteriology from the Indian Veterinary Research Institute , India .
Creating a vaccine would be ideal , but that ’ s proven difficult . Antibodies could be an alternative to an HIV vaccine . A clinical trial of the antibody VRC01 , the first one of its kind has just begun in Brazil , Peru , and the United States . The study will enroll 2,700 people who are at high-risk of infection and it will test how effectively the antibody protects them from getting infected . Later , the study will launch in several African nations , including South Africa , Kenya , Botswana , and Tanzania . If the results , which are expected by 2022 , are good , antibodies could be developed into an effective preventive treatment , which would be profoundly important in the fight against HIV .
Funding support
While the National Institute of Allergy and Infectious Diseases ( NIAID ), a component of National Institutes of Health ( NIH ) funded this project , the Rockefeller University , New York and Vaccine Research Center , NIH were the main collaborators .
BIOVOICENEWS . COM 43
“
Staff Scientist at the National Institute
of Allergy and Infectious Disease while
talking about the issue of long term
efficacy of a passive antibody transfer
for HIV1, says, “We found that enough
concentration of monoclonal
antibodies stays in body for long time
and blocks infection when repeatedly
exposed to HIV.”
While main challenge was to develop
a model which replicates practical
situation where humans are exposed
repeatedly to very low copies of HIV
resulting in infection, Rajeev says
that they are in process of testing
long-acting versions of these
antibodies to achieve an annual
administration of monoclonal
antibodies for full protection.
This kind of HIV Vaccine would be
great for the under developed African
countries as well as developing Asian
nations where people can't afford
expensive HIV-AIDS treatment. “HIV
is a number one killer among infectious
diseases in African countries and rate
of new HIV infections are consistently
increasing in Asian countries. Without
any doubt, vaccine is the need of an
hour but HIV is very notorious as it
changes itself very fast to escape any
counter effect,” he says while pointing
towards the long road ahead.
More about the experiments and
proof of concept
As per Rajeev, the majority of HIV
infections are transmitted via mucosal
route therefore repeated mucosal low
dose challenge in Indian rhesus
macaque was used to test the efficacy
of antibodies.
They had examined "passive
immunisation" as an alternative to an
HIV vaccine, which experts fear may
still be years off. A vaccine works by
priming the body to respond with
germ-fighting antibodies whenever a
virus or bacteria invades. It is longlasting, sometimes for life.
"Passive immunisation" involves the
transfer of antibodies generated by
one person directly to another to
provide protection, which is shorter
in duration.
In the study, researchers used four
We found
that enough
concentration of
monoclonal
antibodies stays in
body for long time
and blocks infection
when repeatedly
exposed to HIV.
DR RAJEEV GAUTAM
With over 14 years of research
experience, Dr Rajeev Gautam
holds PhD in bacteriology from
the Indian Veterinary Research
Institute, India.
powerful antibodies that are known for
neutralizing several strains of HIV
circulating around the world. The
antibodies were produced by certain
HIV-infected people and purified in a
lab before being used in the study. The
researchers injected four groups of
macaques with a different antibody. A
week after the monkeys were given the
antibodies, they were exposed to
weekly low doses of a monkey version
of the HIV virus. (The human version
only infects people.) The antibodies
were found to protect the macaques
from becoming infected for 12 to 14
weeks on average. Some animals were
even protected for as long as 23 weeks.
For monkeys without the antibody, it
took an average of three weeks to
become infected with HIV.
How is it different?
While the antibodies have already been
used to delay HIV infection in
macaques, in most of those studies, the
monkeys were infected with HIV with a
single high-dose shot of the virus.
Whereas, in this study, the monkeys
were instead exposed to the virus in
low doses week by week, not all at once.
That mimics the way that people get
exposed to HIV in real life. In fact,
people usually don’t get infected with
HIV the first time they’re exposed to
the virus.
While the preventive HIV medications
already exist, but they still can’t give
the completely desired results. Pills like
PrEP, for example, reduce the risk of
getting infected from sex by more than
90 percent. The problem is that these
need to be taken daily, and people often
forget or they run out of pills or they
take the medication only when they
have sex. And that reduces the drug’s
effectiveness. This is why scientists are
looking for other medications that can
prevent HIV infections.
Way forward
Creating a vaccine would be ideal, but
that’s proven difficult. Antibodies could
be an alternative to an HIV vaccine. A
clinical trial of the antibody VRC01, the
first one of its kind has just begun in
Brazil, Peru, and the United States. The
study will enroll 2,700 people who are
at high-risk of infection and it will test
how effectively the antibody protects
them from getting infected. Later, the
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