Author Archives: rikul thapar

What triggers Allergies?



Some of the things that we’re allergic to – such as peanuts and pollen, for example – carry compounds that resemble proteins found in parasites. It is found that allergic reactions are actually miscommunicated immune responses: For our own protection, our bodies produce antibodies, which attack similar but harmless compounds. The action of an antibody on a harmful compound can be described through the following video:

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Various environmental and food proteins called allergens are recognized by an immune system antibody called immunoglobulin E (IgE). This part of the mammalian immune system is thought to have evolved as an additional rapid response mechanism to combat parasitic arthropods and worms called helminths. If IgE-mediated immune responses evolved to provide extra protection and not to cause allergic reactions,  then environmental allergens such as pollen should share key molecular properties with the parasite antigens that are specifically targeted by IgE in infected humans.antibodz

To test this, a team led by Nidhi Tyagi from the EMBL-European Bioinformatics Institute identified epitopic-like regions in 206 parasitic proteins and as the first example, it was found that a plant protein (BetV1) has similar binding sites for anti bodies, as it is found for allergens such as pollen in a worm. This confirms that the immune system targets allergens (Both plant protein and harmful parasites) via IgE antibodies and causes immune responses which fail to differentiate between useful and harmful compounds.

Their research also helped them to list 2,445 parasite proteins that show significant similarity in both sequence and structure with allergenic proteins, which can cause immune response against useful proteins. The research team then measured antibody responses in blood collected from 222 people living in the fishing village of Namoni on the shores of Lake Victoria in Uganda. These community members were suffering from schistomsomiasis which is caused by the worm Schistosoma mansoni(pictured below). The blood was collected immediately before anti-schistosomiasis treatment and five weeks afterwards.


It turned out that a plant protein called BetV1 – the commonest allergen in pollen – is a target of IgE in humans infected with schistosomiasis.

Tyagi’s research adds to one of those definitions: environmental and food proteins that are similar to those parasite proteins against which IgE is an observed marker of protective immunity. Defining allergen-like molecules in parasites and understanding their link to the unregulated IgE response, will help with the discovery and design of molecules for future treatment of allergic conditions.


New AIDS vaccine trials to be performed on Humans for the first time in history

In 1984, Human immunodeficiency virus (HIV) was discovered by a team led by Dr. Roberto Gallo, which opened the gates for mankind in order to gain more knowledge about this deadly incurable disease which was the reason for the deaths of millions of people. As the director of the Institute of Human Virology (IHV), Dr. Roberto Gallo is now launching the institute’s first clinical trial of a vaccine for AIDS – a project that has been 15 years in the making.

HIV is one of a group of atypical viruses called retroviruses that maintain their genetic information in the form of ribonucleic acid (RNA). HIV virus has an enzyme known as reverse transcriptase, which makes it capable of producing deoxyribonucleic acid (DNA) from RNA, whereas most cells carry out the opposite process, transcribing RNA from DNA. The activity of the enzyme enables the genetic information of HIV to become integrated permanently into the genome (chromosomes) of a host cell. Since HIV virus controls the genetic information of the cell, it makes the cell produce more HIV virus using the host machinery, thus replicating at a fast rate. With HIV’s inherent ability to rapidly mutate and escape the immune system, conceiving an effective vaccine against it has been a seemingly difficult challenge.
Mechanism of HIV virus invading a human cell

Mechanism of HIV virus invading a human cell

It is found that when HIV infects a person, its surface protein called gp120 attached itself to another protein called the CD4 receptor, which is found in the white blood cells. When it binds to CD4 cell, it can change shape to avoid recognition from neutralizing antibodies which is the usual immune response form the body. This conformational change allows it to bind to a second receptor called a co-receptor, on CD4 cell surface. Once it has a grip on both HIV envelope protein fuses with the cell membrane, thus once within the cell, HIV is safe from attacks from antibodies. 
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The experimental AIDS vaccine, called as “Full length single chain” vaccine contains an HIV surface protein gp120, engineered to link to a few portions of the CD4 receptor. The main aim is to trigger antibodies against gp120 surface protein when it’s already attached to CD4 and the transitional state in which the protein envelope is present is vulnerable to be attacked, thus effectively stopping it from attaching to the second site of co-factor attachment.
According to World Health Organization (WHO), AIDS has been held responsible for over 1.2 million people in the year 2014, if this vaccine turns out to be effective, it could change the world.
-Rikul Thapar