In developing immunity to allergens, a little ‘dirty’ goes a long way

What has been known for long time gets confirmed again and again! The more and early exposure to potential allergens helps to prevent allergies!

How many more times does this need to be confirmed? This seems to be kind of redundant research!

"... 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. ...

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. ..."

From the abstract:

"Allergic diseases are caused by overexuberant type II immune responses mounted against environmental antigens. The allergic state is typified by the presence of allergen-reactive immunoglobulin E (IgE), which triggers mast cell degranulation upon allergen encounter, manifesting in pruritis, oedema and, in severe cases, anaphylaxis.

Over the past century, the prevalence of allergic diseases has increased markedly, suggesting that environmental rather than genetic factors are mediating this change. Although many hypotheses connecting environment to allergy exist, the biological mechanisms that underpin environmentally mediated protection from allergy are unknown.

Here we show, using a mouse model of allergic disease, that exposure to immunostimulatory environments generated cross-reactive adaptive immune memory, which tracked with obstructed type II immune responses upon allergen exposure. We found that engagement of cross-reactive adaptive immunity protected against future allergic sensitization and suppressed established allergic responses.

Cross-reactivity in a tolerogenic context also prevented allergy, with the effect extending across antigenically complex exposures even at low protein sequence similarity. Our findings demonstrate a mechanistic relationship between environment and allergy, with general implications for adaptive immune function in natural settings."

In developing immunity to allergens, a little ‘dirty’ goes a long way | Yale News "New Yale research finds that microbe-diverse environments build protective immune memory that helps prevent allergies. "

Environmentally driven immune imprinting protects against allergy (open access)

Fig. 2: Pet shop mice have pre-existing immune memory of model antigens.