Summary:
This study reviewed how the immune system in early life is shaped by microbial and maternal inputs, rather than developing on its own. The authors highlight that the microbiota play a crucial role in maintaining immune equilibrium by regulating immune cell activity, guiding organ maturation, and promoting tolerance to beneficial and harmful microbes. The researchers described how in the first few weeks of life, certain bacteria such as Streptococcus spp. colonise the infant’s mouth and influence the later formation of microbial communities by occupying binding sites and altering the local environment. Moreover, the study emphasises that disruptions to early oral or gut colonisation may influence the development of both oral and systemic diseases. For example, the oral microbiome has been linked to weight gain, rheumatoid arthritis and autism. The authors propose that prenatal and early postnatal factors including maternal microbiota, mode of delivery, breastfeeding, antibiotic exposure and environment, shape the infant’s microbiota and immune trajectories during the critical “first 1,000 days” (from conception to two years of age). In summary, this study draws attention to the co-development of the microbiome and immune system in early life, and argues that this window is especially important for lifelong immune health and disease risk.
Abstract:
The first 1, 000 days of life, from the fetal stage of a woman’s pregnancy to 2 years of age after the baby is born, is a critical period for microbial colonization of the body and development of the immune system. The immune system and microbiota exhibit great plasticity at this stage and play a crucial role in subsequent development and future health. Two-way communication and interaction between immune system and microbiota is helpful to maintain human microecological balance and immune homeostasis. Currently, there is a growing interest in the important role of the microbiota in the newborn, and it is believed that the absence or dysbiosis of human commensal microbiota early in life can have lasting health consequences. Thus, this paper summarizes research advances in the establishment of the oral and intestinal microbiome and immune system in early life, emphasizing the substantial impact of microbiota diversity in the prenatal and early postnatal periods, and summarizes that maternal microbes, mode of delivery, feeding practices, antibiotics, probiotics, and the environment shape the oral and intestinal microbiota of infants in the first 1, 000 days of life and their association with the immune system.
Article Publication Date: 21/01/2025
DOI: 10.3389/fped.2025.1471743
