Studying immune response to aluminum salts can explain how these chemicals boost vaccine's efficacy

June 28, 2017, Agency for Science, Technology and Research (A*STAR), Singapore

Adjuvants are often included in vaccines to stimulate the immune system and so make a vaccine more effective. Now an A*STAR team, led by Alessandra Mortellaro from the Singapore Immunology Network, has explained a new immune pathway of a commonly used vaccine adjuvant, aluminum salts or 'alum'.

Components of disease-causing microorganisms contained in vaccines are not always sufficient to elicit a strong immune response. In some cases, unrelated chemicals, called adjuvants, are needed to further stimulate the immune system. The A*STAR team has taken up the challenge of explaining this enigma, known as the "immunologist's dirty little secret".

The immunity-boosting effect of was discovered in the 1920s: scientists in London found that aluminum potassium sulfate enhanced the efficacy of diphtheria vaccines considerably. Nowadays, alum is included in inoculations against various diseases, including common ones such as seasonal flu, tetanus and . Paradoxically, despite the fact that millions of doses of aluminum-containing jabs have helped prevent and eradicate several pathologies, the details of alum's mechanism of action are not fully confirmed.

Mortellaro's team discovered that alum triggers immune called (DCs), to release IL-2 proteins. These act as a bridge between innate immunity and immunological memory. The former defends the organism against any foreign substances entering the body, while the latter is specific for a certain infectious agent and can quickly detect and attack it upon subsequent encounters.

By injecting an alum-adjuvated to mice which are either able or unable to produce DC-derived IL2, the team found that this protein is required to spark and memory against the vaccination's target.

"We found that the release of DC-derived IL-2, promoted by alum, produces the typical signs of an efficient long-term immunization, where white blood T cells help other (B cells) to differentiate into antibody-producing cells," explains Mortellaro. Specifically, the researchers found an increase in both in the number of CD4+ T cells and of antibodies specific for the antigen present in the vaccine.

The release of DC-specific IL-2 is the last step of a molecular pathway, of which A*STAR scientists clarified the specifics. "It is an immune pathway shared by mouse and man, so these findings on alum and mouse immunity could be translated into the clinic," Mortellaro points out. "Moreover, we can leverage the knowledge about this pathway to improve vaccine formulation and development, and to test whether new adjuvants and alum alternatives have the same effect on DCs."

Explore further: Vaccine adjuvant uses host DNA to boost pathogen recognition

More information: Hanif Javanmard Khameneh et al. The Syk–NFAT–IL-2 Pathway in Dendritic Cells Is Required for Optimal Sterile Immunity Elicited by Alum Adjuvants, The Journal of Immunology (2016). DOI: 10.4049/jimmunol.1600420

Related Stories

Vaccine adjuvant uses host DNA to boost pathogen recognition

April 5, 2013
Aluminum salts, or alum, have been injected into billions of people as an adjuvant to make vaccines more effective. No one knows, however, how they boost the immune response. In the March 19, 2013, issue of the Proceedings ...

Adjuvant combo shows potential for universal influenza vaccine

June 8, 2011
Researchers at National Jewish Health have discovered how to prime a second arm of the immune system to potentially boost influenza vaccine effectiveness. A combination of two adjuvants, chemicals used to boost the effectiveness ...

Infant-friendly flu vaccine developed with key protein

January 19, 2016
According to the World Health Organization, influenza causes serious illness among millions of people each year, resulting in 250,000 to 500,000 deaths. Those most at risk include infants younger than six months, because ...

How white blood cells jump into action in response to foreign microbes

September 21, 2016
Pro-inflammatory molecules in the blood are essential for fighting off microbial invaders. But too much of these immune-signaling factors, and the body can go into septic shock. A team from the A*STAR Singapore Immunology ...

Recommended for you

A synthetic approach to helping the immune system thwart infections

February 22, 2018
Yale researchers have developed a set of synthetic molecules that may help boost the strength of a key, virus-fighting protein.

Scientists find molecular link between Vitamin A derivative and mouse intestinal health

February 22, 2018
New research shows that all-trans-retinoic acid (atRA), the active form of vitamin A, regulates immune system responses in the mouse intestine by controlling expression of the protein HIC1 in cells known as innate lymphoid ...

Animal study shows how to retrain the immune system to ease food allergies

February 21, 2018
Treating food allergies might be a simple matter of teaching the immune system a new trick, researchers at Duke Health have found.

'Icebreaker' protein opens genome for T cell development, researchers find

February 20, 2018
Almost all cells in the human body have identical DNA sequences, yet there are 200-plus cell types with different sizes, shapes, and chemical compositions. Determining what parts of the genome are read to make protein and ...

Preventive treatment for peanut allergies succeeds in study

February 20, 2018
The first treatment to help prevent serious allergic reactions to peanuts may be on the way. A company said Tuesday that its daily capsules of peanut powder helped children build tolerance in a major study.

Infection site affects how a virus spreads through the body

February 20, 2018
A person is more likely to get infected by HIV through anal intercourse than vaginal, but no one knows quite why. A new study by scientists at the Gladstone Institutes shows that infection sites could affect the immune system's ...

1 comment

Adjust slider to filter visible comments by rank

Display comments: newest first

Nik_2213
not rated yet Jun 28, 2017
So, how long before anti-vaxxers begin blaming the aluminium adjuvants instead of the mercury non-content ??
10, 9, 8, 7...

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.