A new study has pointed out that exposure of pregnant mothers to bacteria in the environment may protect kids from allergies.
The research team from Marburg, Germany showed that exposure to microbes triggers a mild inflammatory response in pregnant mice that renders their offspring resistant to allergies.
Continuous rise in allergies in the past several decades is often attributed to an increasing tendency to keep kids too clean-a theory known as the hygiene hypothesis.
According to this theory, exposure of young children to environmental microbes conditions the developing immune system to tolerate microbes and allergens later in life.
Previous studies have shown that children raised on farms, which teem with microbes, developed fewer allergies than those raised in cities or non-farming rural regions.
The new study led by Harald Renz at the Phillips-University of Marburg showed that pregnant mice exposed to inhaled barnyard microbes gave birth to allergy-resistant pups.
The exposure triggered a mild inflammatory response in the moms, characterized by the increased expression of microbe-sensing "Toll-like" receptors (TLRs) and the production of immune molecules called cytokines.
The maternal TLRs were essential for transmitting protection, but how TLR signals translate into allergy resistance in the offspring is not yet known.
The study appears in the Journal of Experimental Medicine.