Mother's exposure to toxins impairs children's immunity

That exposure to pollution harms health is not new to anyone, but a study developed at the University of Rochester and published in iScience suggests that ubiquitous exposure to industrial pollution can damage immunity for generations, weakening the body's defenses against infections such as the influenza virus, from mothers, children, grandchildren, great-grandchildren, and so on.

Paige Lawrence of the department of environmental medicine at the University of Rochester Medical Center explains that the study suggests that impacts on the immune system can be felt for generations. She says that while other studies have shown that exposure to pollutants can impact reproductive, respiratory and nervous system functions for generations, current research has unheardly shown that exposure also affects immunity.

Researchers explain that multigenerational weakening of immunity may help explain variations during seasonal and pandemic influenza episodes, as annual vaccines provide more protection for some people than others. In addition, during outbreaks of pandemic influenza, some people become seriously ill while others fight the infection.

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Some factors, such as age and virus mutation, may explain this variation, but the diversity of responses has other aspects involved. “When you get infected or get a flu shot, the immune system increases the production of specific types of white blood cells in response. The greater the response, the larger the army of white blood cells, increasing the body's ability to successfully fight an infection. Having a smaller army - what we see in several generations of mice in this study - means you risk not fighting the infection as effectively, ”explains Lawrence.

Mouse Test Proves Low Immunity in Mothers, Children, “Grandchildren” and “Great-Grandchildren”

To conduct the study, researchers exposed pregnant mice to dioxin at environmentally relevant levels. A common by-product of industrial production and waste incineration, and found in some consumer products, these chemicals enter the food system and are eventually consumed by humans. Dioxins accumulate as they progress through the food chain and animal products have a higher concentration.

The production and function of cytotoxic T cells - white blood cells that defend the body from foreign pathogens as well as looking for and destroying cells with mutations that can lead to cancer - were impaired when mice were infected with influenza A virus. And the immune response weakened went beyond. Not only did the offspring of dioxin-exposed mothers show poor immunity, but subsequent generations, including even “great-grandchildren, ” with the most intense effect on females.

The hypothesis of the researchers is that dioxin exposure alters the transcription of genetic instructions, ie, it is not the exposure that triggers a mutation, but the mechanism by which genes are expressed that changes and is passed on to subsequent generations.