Conventional wisdom has held for some time that children who grow up in environments rich with biodiversity - farms, homes with pets, rural settings in general - are less likely to have allergies. The thing nobody has ever completely understood is why?
Yale researchers have now found an answer. It turns out that exposure to diverse microbes and proteins early in life creates broad immune memory and a specific antibody that helps block allergic reactions later in life. Rather than overreacting to harmless allergens (ragweed, cats, peanuts, etc.), researchers say, an experienced immune system responds in a balanced way.
The findings may inform better strategies for allergy prevention, encouraging early exposure to natural environments and new therapies that boost protective immune responses rather than just suppressing symptoms.
The all-Yale study is published in the journal Nature.
"We wanted to test this idea that living in a less clean environment protects you from allergies," said Ruslan Medzhitov, the Sterling Professor of Immunobiology at Yale School of Medicine and first author of the study. "The main question we wanted to answer was what's happening to the immune system when you're in a natural environment and exposed to a lot of microbes?"
To find out, researchers compared two groups of mice. One group consisted of mice raised in microbe-rich environments - akin to mice living in a natural habitat. The other group consisted of laboratory mice raised in sterile conditions. Researchers exposed both groups to allergens and then measured allergic reactions, antibody production, and immune cell activity in the animals.
