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

New inflammation inhibitor discovered

November 16, 2018
A multidisciplinary team of researchers led from Karolinska Institutet in Sweden have developed an anti-inflammatory drug molecule with a new mechanism of action. By inhibiting a certain protein, the researchers were able ...

Pets can double as asthma antidote

November 16, 2018
(HealthDay)—The "hygiene hypothesis" holds that early exposure to a variety of microorganisms may decrease the risk for chronic inflammatory diseases, like asthma.

New study shows NKT cell subsets play a large role in the advancement of NAFLD

November 16, 2018
Since 2015 it has been known that the gut microbiota could have a direct impact on nonalcoholic fatty liver disease (NAFLD), which affects up to 12% of adults and is a leading cause of chronic liver disease. In the November ...

A gut bacterium as a fountain of youth? Well, let's start with reversing insulin resistance

November 16, 2018
Move over Bifidobacterium and Lactobacillus. There's a new health-promoting gut bacterium in town, and it's called Akkermansia muciniphila.

Defense against intestinal infection in organism is affected by prostaglandin E2

November 15, 2018
The treatment of intestinal infections caused by some strains of the bacterium Escherichia coli, present in unsanitized or contaminated foods, may have a new ally.

No link between 'hypoallergenic' dogs and lower risk of childhood asthma

November 15, 2018
Growing up with dogs is linked to a lower risk of asthma, especially if the dogs are female, a new study from Karolinska Institutet and Uppsala University in Sweden shows. However, the researchers found no relation between ...

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.