The UK-based team suggests exposure of the new-born baby to maternal cells through breastfeeding promotes maturation of immune cells called regulatory T cells, also helping to reduce inflammation.
“The influence of the type of milk received on the development of the immune response has not previously been studied in the first few weeks of life,” explains senior study author Dr Gergely Toldi, a researcher at the University of Birmingham.
“Prior to our research the outstanding importance and the early involvement of this specific cell type in breastfed babies was unknown.
“We hope this invaluable new insight will lead to an increase in rates of breastfeeding and will see more babies benefit from the advantages of receiving breastmilk,” adds Dr Toldi, who is also consultant neonatologist at Birmingham Women's and Children's NHS Foundation Trust, said:
“Furthermore, we hope for those babies who are formula fed, these results will contribute to optimising the composition of formula milk in order to exploit these immunological mechanisms.
Veillonella and Gemella
Current understanding of how the neonatal immune system develops, particularly in the first few weeks of life and the role of breastfeeding, remains limited.
The establishment of the gut microbiome before and after the birth of a child is likely to be a main factor in the neonatal immune development.
Indeed, colonisation with specific commensal bacteria can enhance the development of regulatory T cell (Tregs) responses, whilst dysbiosis disturbs immune development and promotes T cell activation.
The Birmingham University team found that specific bacteria, called Veillonella and Gemella, which support the function of these regulatory T cells, are more abundant in the gut of breastfed babies.
“The natural nutrition for neonates is from breastmilk which contains a range of complex nutrients as well as antimicrobial proteins,” the paper states.
“Breastmilk also contains bacteria and maternal cells, and as such it is not surprising that exposure to either breastmilk or formula milk significantly influences the composition of the gut microbiome.
“Differential microbiome composition is likely to act as an indirect influence on how nutrition can modify the neonatal immune profile but there may also be a direct effect from exposure to maternal cells and antigenic proteins within milk.”
Along with colleagues from the Birmingham Women’s and Children’s hospital and the Institute of Cancer and Genomic Sciences, the team enrolled 38 healthy mothers and their healthy babies onto the three-year project.
Small amounts of blood and stool samples were collected at birth at Birmingham Women’s Hospital and then again later during home visits when the babies were three weeks old.
Sixteen out of the 38 babies (42%) were exclusively breastfed for the duration of the study, while nine babies received mixed feeding and 13 babies were exclusively formula-fed.
The team noted a striking finding that saw Tregs expand substantially in the first three weeks of life with this expansion more profound in breastfed babies in contrast to those receiving formula feed.
Previous research looking into the Tregs of breastfed neonates found these babies exhibited an activated phenotype with increased expression of HLA-DR, a marker of increased suppressive activity.
In observing that the gut microbiome of breastfed neonates was more abundant in Gemella and Veillonella, the team cited a study linking the presence of Veillonella and the proportion of Tregs at three weeks of age.
“Furthermore, a recent study demonstrated a lack of Veillonella and other anaerobic taxa in the microbiome of extremely preterm infants with postnatal growth failure compared to appropriate postnatal growth, indicating its role in early metabolic programming. The relative abundance of Veillonella further increases by two months of age.”
The researchers hope to now further study this biological mechanism in sick and pre-term newborn babies who have developed inflammatory complications.
Source: Basic and Translational Allergy Immunology
Published online: DOI: 10.1111/all.14736
“Breastfeeding promotes early neonatal regulatory T cell expansion and immune tolerance of non-inherited maternal antigens.”
Authors: Wood et al