Breast Milk: Proactive Immunomodulation and Mucosal Protection Against Viruses and Other Pathogens

Authors and Disclosures

Chiara Cerini¹ & Grace M Aldrovandi*<sup>1

1</sup>Department of Pediatrics & Molecular Microbiology & Immunology, Children's Hospital Los Angeles, University of Southern California, Los Angeles, CA, USA

Financial & competing interests disclosure
The authors have no relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript. This includes employment, consultancies, honoraria, stock ownership or options, expert testimony, grants or patents received or pending, or royalties.
No writing assistance was utilized in the production of this manuscript.

*Author for correspondence
Tel.: +1 323 361 2509 Fax: +1 323 361 2661 galdrovandi@chla.usc.edu

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Executive Summary

Breast Milk Antibodies

• Breast milk contains high concentration of secretory antibodies, mainly IgA, with a broad range of specificities reflecting both maternal immunologic memory and antigenic stimulation of maternal mucosal associated lymphoid tissue.

• Secretory IgA is resistant to degradation and provides passive protection via multiple mechanisms.

Other Factors in Milk

• Breast milk contains more than 100,000 constituents that influence the baby's growth, development and immune status.

Mechanisms of Infant Protection

• Breast milk immune factors – mainly sIgA – act either as protective and proactive factors and sustain the development of the infant's immune system.

• The active stimulation of the infant's immune system by breastfeeding shapes the baby's gut microbiota, facilitates the development of tolerance, regulates the inflammatory response and promotes responses to vaccines.

Maternal Immunization

• Antenatal maternal immunization has been extremely successful in controlling some diseases; however concerns have arisen about blunting the infant's response to his/her own vaccinations due to passively acquired maternal antibodies. Postnatal maternal immunizations aimed to enhance breast milk antibodies production might be a promising approach.

Conclusion

• In addition to being the best source of nutrition for the offspring, human milk is a complex and dynamic secretion that contains a myriad of protective factors against infectious disease and may influence the infant's immune system development.

• Further studies are needed to understand the types of vaccines and routes of administrations that promote the production of protective antibodies in breastfeeding mothers.