Microbial Transfer from Mother to Newborn Affects Lung Immunity

A new study published in the journal Cell Reports shed light on the role of γδ T cells in the transfer of maternal microbiota during birth and nursing and the impact on the lung immune response in newborns. The research was led by Bruno Silva Santos, group leader and vice-director at the Instituto de Medicina Molecular João Lobo Antunes in Portugal.

The lungs of newborns are filled with sterile liquid that is replaced by air in the first breath, causing an immune reaction known as the “first breath response.” The study found that this immune response in mice is influenced by γδ T cells, and newborns born to mothers without these cells acquire a different gut microbiota. This results in an exacerbated first breath immune response, as the intestinal microorganisms in these mice cannot produce enough of a specific molecule important for modulating the lung immune response.

The researchers also observed a similar pattern in the offspring of mothers lacking γδ T cells in response to a lung-damaging parasite infection. Supplementing with short-chain fatty acids, which were found to be lacking in mice with exacerbated immune responses, or treating with antibiotics to kill the gut microorganisms abolished the differences between the mice born to mothers with and without γδ T cells. This shows that the effects observed in the offspring are indirectly linked to the molecules produced by the gut microbiota.

The study also found that microbiota transfer from mothers to newborns is not restricted to the birth process. If newborns born to mothers without γδ T cells are raised by mothers with these cells, their immune response is restored. This suggests that the majority of the bacterial communities must be transferred after birth during nursing.

The researchers discovered that maternal γδ T cells play a role in developing newborns’ lung immunity by exerting an effect on the colonization of gut microorganisms. This adds to the growing body of evidence on the physiological and therapeutic roles of the gut microbiota and how vertically transferred cues from mothers influence the development of the immune system.

This study highlights the importance of considering maternal factors when designing experiments using genetically engineered mice. Maternal transfer of bacteria and external cues during early life can have long-lasting effects on the immune system, and alternative approaches such as co-housing and genetic background matching should be considered in biomedical research.