Breastmilk-saliva interactions boost innate immunity by regulating the oral microbiome in early infancy

Al-Shehri, Saad S., Knox, Christine L., Liley, Helen G., Cowley, David M., Wright, John R., Henman, Michael G., Hewavitharana, Amitha K., Charles, Bruce G., Shaw, Paul N., Sweeney, Emma L. and Duley, John A. (2015) Breastmilk-saliva interactions boost innate immunity by regulating the oral microbiome in early infancy. PLoS One, 10 9: e0135047.1-e0135047.19. doi:10.1371/journal.pone.0135047

Author Al-Shehri, Saad S.
Knox, Christine L.
Liley, Helen G.
Cowley, David M.
Wright, John R.
Henman, Michael G.
Hewavitharana, Amitha K.
Charles, Bruce G.
Shaw, Paul N.
Sweeney, Emma L.
Duley, John A.
Title Breastmilk-saliva interactions boost innate immunity by regulating the oral microbiome in early infancy
Journal name PLoS One   Check publisher's open access policy
ISSN 1932-6203
Publication date 2015-09-01
Sub-type Article (original research)
DOI 10.1371/journal.pone.0135047
Open Access Status DOI
Volume 10
Issue 9
Start page e0135047.1
End page e0135047.19
Total pages 19
Place of publication San Francisco, CA, United States
Publisher Public Library of Science
Collection year 2016
Language eng
Formatted abstract
Introduction: Xanthine oxidase (XO) is distributed in mammals largely in the liver and small intestine, but also is highly active in milk where it generates hydrogen peroxide (H2O2). Adult human saliva is low in hypoxanthine and xanthine, the substrates of XO, and high in the lactoperoxidase substrate thiocyanate, but saliva of neonates has not been examined.

Results: Median concentrations of hypoxanthine and xanthine in neonatal saliva (27 and 19 μM respectively) were ten-fold higher than in adult saliva (2.1 and 1.7 μM). Fresh breastmilk contained 27.3±12.2 μM H2O2 but mixing baby saliva with breastmilk additionally generated >40 μM H2O2, sufficient to inhibit growth of the opportunistic pathogens Staphylococcus aureus and Salmonella spp. Oral peroxidase activity in neonatal saliva was variable but low (median 7 U/L, range 2–449) compared to adults (620 U/L, 48–1348), while peroxidase substrate thiocyanate in neonatal saliva was surprisingly high. Baby but not adult saliva also contained nucleosides and nucleobases that encouraged growth of the commensal bacteria Lactobacillus, but inhibited opportunistic pathogens; these nucleosides/bases may also promote growth of immature gut cells. Transition from neonatal to adult saliva pattern occurred during the weaning period. A survey of saliva from domesticated mammals revealed wide variation in nucleoside/base patterns.

Discussion and Conclusion: During breast-feeding, baby saliva reacts with breastmilk to produce reactive oxygen species, while simultaneously providing growth-promoting nucleotide precursors. Milk thus plays more than a simply nutritional role in mammals, interacting with infant saliva to produce a potent combination of stimulatory and inhibitory metabolites that regulate early oral–and hence gut–microbiota. Consequently, milk-saliva mixing appears to represent unique biochemical synergism which boosts early innate immunity.
Q-Index Code C1
Q-Index Status Confirmed Code
Institutional Status UQ
Additional Notes

Document type: Journal Article
Sub-type: Article (original research)
Collections: Mater Research Institute-UQ (MRI-UQ)
Official 2016 Collection
School of Pharmacy Publications
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Citation counts: TR Web of Science Citation Count  Cited 3 times in Thomson Reuters Web of Science Article | Citations
Scopus Citation Count Cited 3 times in Scopus Article | Citations
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Created: Fri, 18 Sep 2015, 15:49:13 EST by Ms Felicity Lindberg on behalf of School of Pharmacy