Gut microbes from healthy infants block milk allergy development in mice.

There has been a conspicuous increase in life-threatening food allergies in societies adopting or hosting Western-based culture. One hypothesis to explain this rising morbidity in a highly specific demographic is that current lifestyle practices, such as overuse of antibiotics, chemical environmental agents, a rise in formula feeding, dietary changes, and higher rates of Caesarean birth have altered the human gut microbiome, the collective genome of bacteria, archaea, fungi, protists and viruses which live in the human gut.  Now, a study from researchers at the University of Chicago shows that gut microbiota may help prevent the development of cow’s milk allergy. The team state their findings may help to develop microbiome-based therapies to prevent or treat food allergy.  The study is published in the journal Nature Medicine.

Previous studies show that infants allergic to cow’s milk had different compositions of gut microbes than non-allergic infants. Research has also revealed that some microbes are associated with a lower risk of developing food allergy, leading to the theory that gut microbes of infants without milk allergy might be protective.  The current study shows germ-free mice colonized with bacteria from healthy, and not cow’s milk allergic (CMA), infants were protected against anaphylactic responses to a cow’s milk allergen.

The current study transplants gut microbes from eight infant donors into groups of mice sensitized to milk protein so their immune systems create antibodies to milk. Results show that when exposed to milk, mice receiving no microbes or microbiota from milk-allergic children produce allergic antibodies and experience anaphylaxis, a potentially life-threatening allergic reaction; mice receiving gut microbes from non-allergic infants had no reactions.  Data findings show mice which receive microbes from non-allergic infants express different genes compared to those that did not, suggesting that microbes residing in the gut impact the host’s immune system.

The group state when microbes in infant stool samples were analysed, many differences between the stool of infants who were allergic to milk and those who were not was found. They go on to add that mice transplanted with microbes from non-allergic infants also housed a family of microbes previously found to protect against developing food allergies; one microbe in particular, Anaerostipes caccae, was isolated and shown to prevent the development of milk allergy when transplanted alone into groups of mice.

The team surmise their data demonstrates that microbiota gut regulate allergic responses to dietary antigens.  For the future, the researchers state that further research could lead to interventions which modulate bacterial communities to counteract food allergy.

Source: National Institutes of Health


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