Monday January 20, 2020

Scientists hopeful of ‘full-length single chain’ AIDS vaccine

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www.pbs.org

NewsGram Staff Writer

Robert Gallo, the scientist who first proved in 1984 that HIV triggered the disease AIDS, is again all set to begin the trial of its vaccine in the US. The vaccine which has been developed over the past 15 years by Gallo is a little different and is expected to bear fruitful results.

The initial phase, involving 60 volunteers, will test the safety and immune responses of the vaccine. This study will reveal whether the vaccine is more effective than the other 100+ AIDS vaccines that have been tested over the last three decades. Extensive testing on monkeys have yielded positive results.

Despite the presence of potential vaccines, the challenge with AIDS is that HIV directly infects white blood cells (RBC) called T-cells, so it literally turns our immune system against us. So, once the virus enters a T-cell, it’s invisible to the immune system.

The sole possibility to combat the threat is to pump in antibodies against the HIV surface proteins. However, doing so is equally difficult owing to the fact that the retrovirus can regularly change its viral envelope to hide particular surface proteins.

But Gallo and his team at the Institute of Human Virology in USA believe that they may have now found a moment when the HIV surface protein, known as gp120, is vulnerable to detection – the moment the virus binds with our bodies’ T-cells.

When HIV infects a patient, it first links to the CD4 receptor on the white blood cell. It then transitions, exposing hidden parts of its viral envelope, which allow it to bind to a second receptor called CCR5. Once HIV is attached to both these T-cell receptors, it can successfully infect the immune cell. at this stage, it is impossible to stop its juggernaut.

Gallo’s “full-length single chain” vaccine contains the HIV surface protein gp120, engineered to link to a few portions of the CD4 receptor. The motive is to fuel antibodies against gp120 when it is already attached to CD4 and is in a vulnerable transitional state. The aim of the whole process is effectively stopping it from attaching to the second CCR5 attachment.

Gallo himself admitted to Jon Cohen over at Science that full-length single chain vaccine is a “terrible name”.

The trial is being run in collaboration with Profectus BioSciences, a biotech spin-off from the Institute of Human Virology, and Gallo explained that extreme thorough testing on monkey and getting the fund to develop a human-grade vaccine have resulted in a delay to get to this point.

“Was anything a lack of courage?” he asked Science. “Sure. We wanted more and more answers before going into people.”

Let’s hope that caution pays off, and we may finally have a viable contender for an AIDS vaccine on our hands.

(With inputs from www.sciencealert.com)

Next Story

Mars Losing Water Faster Than Expectations of The Scientists

The ExoMars rover will travel across the Martian surface to search for signs of life

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Mars
Mars today is cold and dry – a desert world -- but dry river valleys and lakebeds suggest that water covered much of the Red Planet billions of years ago. Previous research has also found that Martian water mostly escaped into space. Pixabay

Mars may have been a place brimming with water in the form of seas, lakes and rivers once but all of that evaporated into space as researchers now report that the Red Planet is losing water faster than expected.

Mars today is cold and dry – a desert world — but dry river valleys and lakebeds suggest that water covered much of the Red Planet billions of years ago. Previous research has also found that Martian water mostly escaped into space.

The gradual disappearance of the water occurs when sunlight and chemistry turn water molecules into the hydrogen and oxygen atoms that they are made up of. When they are broken down, Mars’s weak gravity is unable to keep hold of them and they disappear off into space, according to the study, published in the journal Science.

In the new study, an international research team, led partly by Franck Montmessin from French National Centre for Scientific Research in France, revealed that water vapour is accumulating in large quantities and unexpected proportions at an altitude of over 80 km in the Martian atmosphere.

The development was spotted using the Trace Gas Orbiter probe that was sent to the Red planet on board the ExoMars (Exploration of Mars) mission, run by the European Space Agency (ESA) and its Russian counterpart Roscosmos.

Measurements showed that large atmospheric pockets are even in a state of supersaturation, with the atmosphere containing 10 to 100 times more water vapour than its temperature should theoretically allow.

“With the observed supersaturation rates, the capacity of water to escape would greatly increase during certain seasons,” the authors wrote. The researchers point out that seasonal changes were the key factors behind how water vapour was distributed in the Martian atmosphere.

Mars
Mars may have been a place brimming with water in the form of seas, lakes and rivers once but all of that evaporated into space as researchers now report that the Red Planet is losing water faster than expected. Pixabay

The 2020 mission of the ExoMars programme will deliver a European rover and a Russian surface platform to the surface of Mars. A Proton rocket will be used to launch the mission, which will arrive to Mars after a nine-month journey.

The ExoMars rover will travel across the Martian surface to search for signs of life.

ALSO READ: Python Becomes The Most Popular Programming Language for Students in India

It will collect samples with a drill and analyse them with next-generation instruments. ExoMars will be the first mission to combine the capability to move across the surface and to study Mars at depth. (IANS)