Embryos harbor immune cells that already perform adult-like defense functions, study suggests
· Medical Xpressedited by Lisa Lock, reviewed by Robert Egan
Lisa Lock
Scientific Editor
Meet our editorial team
Behind our editorial process
Robert Egan
Senior Editor
Meet our editorial team
Behind our editorial process Editors' notes
This article has been reviewed according to Science X's editorial process and policies. Editors have highlighted the following attributes while ensuring the content's credibility:
fact-checked
peer-reviewed publication
trusted source
proofread
The GIST Add to Preferred Sources
Neutrophils are white blood cells that form part of the body's first line of defense. Researchers have now demonstrated for the first time that neutrophils are found in many tissues during embryonic development, and that they can perform the same functions as adult neutrophils. The findings warrant further study on the role of embryonic neutrophils in tissue development and in responding to infections in fetuses and newborns.
Neutrophils are part of innate immune defense. When inflammation occurs, they rapidly migrate from the bloodstream into tissues to eliminate harmful microbes. Their role is well understood in adults, but little is known about embryonic neutrophils.
During their studies, the researchers from the University of Turku, Finland, discovered that there were large populations of neutrophils in several developing embryonic tissues in mice. Their study is published in the journal Nature Communications.
"We were immediately intrigued. What is the role of these defense cells when the embryo is still safely inside the uterus? The uterus provides an almost sterile environment where there should not yet be any need for rapid defense cells," says doctoral researcher Laura Lintukorpi from the University of Turku.
The researchers used single-cell RNA sequencing, which revealed that embryonic and adult neutrophils differed slightly in their gene expression, although their major developmental stages proved to be similar.
"Embryonic neutrophils were able to perform immune functions typical of adult neutrophils, such as ingesting particles, producing toxic oxygen compounds and forming weblike structures that trap pathogens outside the cell. Embryonic neutrophils are therefore not merely dormant developing cells, but functionally mature cells," says doctoral researcher Julian Hofmann from the University of Turku.
Embryonic neutrophils may have functions beyond immune defense
According to Hofmann, one of the most interesting findings of the study is the distribution of neutrophils in developing tissues. As many of the cells are located outside of the blood vessels, they are in direct contact with the developing tissue cells.
"This suggests that embryonic neutrophils may have functions related to tissue development and homeostasis in addition to those related to immune defense," says Hofmann.
According to docent and InFLAMES research flagship group leader Pia Rantakari from the University of Turku, the study is reshaping our understanding of neutrophils before birth and of the parallel development of the immune system and tissues.
"Our findings from experimental models show that neutrophils play a much more active role in developing tissues than was previously thought. Embryonic neutrophils are a functionally competent cell population adapted to a specific stage of development, rather than just immature versions of adult immune cells," concludes Rantakari.
If neutrophils are also found in human tissues during embryonic development, these findings could contribute to future treatments for prenatal and perinatal infections and inflammatory diseases.
Publication details
Julian Hofmann et al., Tissue-resident neutrophils serve homeostatic and immunological functions in embryos, Nature Communications (2026). DOI: 10.1038/s41467-026-75410-0
Journal information: Nature Communications
Key medical concepts
Clinical categories
Allergy and immunology Provided by University of Turku Who's behind this story?
Lisa Lock
BA art history, MA material culture. Former museum editor, paramedic, and transplant coordinator. Editing for Science X since 2021. Full profile →
Robert Egan
Bachelor's in mathematical biology, Master's in creative writing. Well-traveled with unique perspectives on science and language. Full profile →
Citation: Embryos harbor immune cells that already perform adult-like defense functions, study suggests (2026, October 19) retrieved 20 October 2026 from https://medicalxpress.com/news/2026-10-embryos-harbor-immune-cells-adult.html This document is subject to copyright. Apart from any fair dealing for the purpose of private study or research, no part may be reproduced without the written permission. The content is provided for information purposes only.