When suppressing immunity is a good thing

A receptor, first known for its role in mediating the harmful effects of the environmental pollutant dioxin in our body, is now understood to play other important roles in modulating the innate immune response.

This image shows the AHR-mediated braking mechanism for the regulation of the...
This image shows the AHR-mediated "braking" mechanism for the regulation of the antiviral IFN response.
Source: Akinori TAKAOKA, Hokkaido University

Our immune system is vital as a protective mechanism against foreign agents, including viruses and bacteria. However, an exaggerated immune response can have damaging effects on the body, as is the case in autoimmune diseases, for example. The regulation of this system is thus important.

More than 35 years ago, researchers discovered the aryl hydrocarbon receptor (AHR) as the mediator of dioxin toxicity in the body. When dioxin enters the body, it binds to AHR, which in turn activates target genes that encode proteins, including one called TIPARP. This then goes on to play a role in the body's reactions to the toxic pollutant.

Now, a team of scientists from Japan's Hokkaido University together with colleagues from Canada and Norway have found that AHR also plays a role in regulating the body's innate immune response to viral infections.

By analysing mouse cells deficient in AHR and comparing the results with cells containing AHR, they found that the activation of this receptor by amino acid metabolites negatively regulates the production of an antiviral protein called type I interferon (IFN-I). It does this by activating the gene that encodes the protein TIPARP, which in turn interferes with the pathway that stimulates interferon production upon viral infection. AHR-mediated "braking" mechanism may help protect the host from harmful effects caused by excessive IFN-I activation. Also, AHR might reduce the body's immune response against viral infection during times of stress and nutritional impairments due to the production of substances that activate the receptor.

Identifying the substances and factors that regulate the pathways that are stimulated by AHR activation could have clinical implications for controlling pathological innate immune responses, the researchers say.


Source: Hokkaido University

14.07.2016

Read all latest stories

Related articles

Photo

Risk assessment

Understanding the spread of COVID-19 on public transport

Researchers at Newcastle University are involved in a study to understand the risks of COVID-19 transmission on public transport and to identify the best measures to control it. Known as Project…

Photo

COVID immunity research

Coronavirus re-infection: what we know so far – and the vital missing clues

As President Trump claims that he is immune to COVID-19 and isolated reports emerge of reinfection, what is the truth about immunity to COVID-19? To date, there have been six published cases of…

Photo

Infection with Covid-19

The antiviral effect of innate immunity

Innate immunity is the fastest-acting component of the immune system, but so far little is known about its role during infection with SARS-CoV-2. A few hours after an infection, the body emits an…

Related products

Atlas Genetics - Atlas Genetics io system

Infectious diseases testing

Atlas Genetics - Atlas Genetics io system

Atlas Genetics Ltd
Eppendorf – Mastercycler nexus X2

Research Use Only (RUO)

Eppendorf – Mastercycler nexus X2

Eppendorf AG
Sarstedt – Cell Culture Products

Specialties

Sarstedt – Cell Culture Products

SARSTEDT AG & CO. KG
Sarstedt – Low DNA Binding Micro Tubes

Research Use Only (RUO)

Sarstedt – Low DNA Binding Micro Tubes

SARSTEDT AG & CO. KG
Shimadzu – CLAM-2030

Research Use Only (RUO)

Shimadzu – CLAM-2030

Shimadzu Europa GmbH