Nature: maternal protective antibody protects newborn from intestinal infection

January 23, 2020 / Biovalley BIOON / - -- breast milk has long been considered beneficial to newborns and protects them from certain infections In a new study, researchers from Harvard Medical School found in mice that at least part of the protective effect of breast milk comes from an amazing source: microbes that reside in the gut The relevant research results were recently published in the journal Nature, and the title of the paper is "microbiota targeted material antibodies protect needs from industrial infection" Picture from nature, 2020, DOI: 10.1038/s41586-019-1898-4 They found that antibodies produced in response to a particular organism in the mother's gut are passed to offspring through breast milk and placenta, protecting newborn mice from at least one potentially deadly pathogenic microbe, Escherichia coli These findings add to growing evidence that microbiota - trillions of microbes in the gut, skin, mouth and other parts of mammals, including humans - play a powerful role in disease and health But the new study takes a step further by identifying the mother's microbiome as a source of immunity for newborn babies This further suggests that intestinal microbiota can provide immune protection, even if the mother has not previously been infected with an infection that allows them to produce protective antibodies and pass them on to their offspring "Our results help to explain why newborn pups are protected from certain pathogenic microorganisms, even though their immune system is not sound and they lack contact with them," said Dennis Kasper, a professor of immunology at the blavatnick Institute of Harvard Medical School and the corresponding author of the paper In addition, they increase the possibility that the mother can provide immunity to pathogens for their offspring, even if they have never encountered them in the past " If confirmed in further studies, the findings could provide a basis for designing microbiological therapies for E.coli and other pathogenic organisms, the researchers said "Although preliminary, we hope that these new insights may provide information for the development of vaccines derived from symbiotic microbial molecules to prevent infectious diseases," Kasper said Another treatment may be the use of symbiotic microorganisms as probiotics for the prevention of diarrhoeal diseases " Infectious diarrhea (most commonly caused by E.coli or rotavirus) is the leading cause of malnutrition and the second leading cause of death in children under five years of age worldwide According to the statistics of the World Health Organization (who), it causes 1.7 billion people in the world every year, and takes more than 520000 lives In the absence of any prior microbial contact, the immune system of the newborn is a blank During the first three weeks, the immune protection of the newborn comes from the maternal antibody passed from the mother to the fetus through the placenta during pregnancy, through the birth canal during delivery and through breast milk shortly after delivery In the new study, the researchers looked at genetically engineered newborn mice lacking B cells, which are factories in the immune system that produce antibodies Later, some newborn mice were raised by their mothers, who also had no B cells at birth Other newborn mice are raised by mothers with normal immune systems Mice exposed to maternal protective antibodies were much more resistant to E coli infection than mice not exposed to such antibodies The researchers observed that this was like the immune rejection of a pathogen in a mouse cub In fact, they had 33 times fewer E coli in their intestines than new mice that lacked maternal antibodies In contrast, mice pups that were not exposed to protective antibodies spread E.coli infection The researchers were also able to identify the specific organism responsible for inducing the formation of protective antibodies - a microbe called Pantoea, a member of the Enterobacteriaceae family that exists in the gut of mice and other mammals, including humans In addition, experiments show that these protective antibodies enter the intestine and blood of the newborn through the new Fc receptor, which is a molecular channel on the placenta and can help transfer these antibodies from the mother to the fetus So far, it is known that this receptor can transfer antibody through placenta However, experiments carried out in this new study show that the receptor also absorbs antibodies from human milk and transfers them from the gut to the blood of newborn mice, thus ensuring broader systemic protection outside the gut These experiments showed that adult mice did not transfer protective antibodies from their intestines to the blood because of the loss of function of the new Fc receptor as they grew older (BIOON Com) reference: 1.wen Zheng et al Microbiota targeted mathematical antibodies protect neighbors from industrial infection Nature, 2020, doi:10.1038/s41586-019-1898-4 2.Research in mice shows antibodies derived from mom's gut microbes protect newborns from E coli infection https://medicalxpress.com/news/2020-01-mice-antibodies-derived-mom-gut.html