[Mucosal immune response development: breastfeeding and environmental influence].

Area of Science:

• Immunology
• Developmental Biology
• Gastroenterology

Context:

• The development of the mucosal immune system is a complex process influenced by both prenatal and postnatal factors.
• Gut-associated lymphoid tissues (GALT) begin to form morphologically during fetal development but mature functionally after birth.
• Antigenic exposure, particularly after birth, plays a critical role in initiating immune responses.

Purpose:

• To review the current understanding of mucosal immune response development from fetal life through infancy.
• To highlight the timing of immunocyte migration, lymphoid tissue development, and functional activation.
• To examine the influence of environmental factors, such as breastfeeding, on mucosal immunity.

Summary:

• Immunocyte migration to mucosal surfaces is an early fetal event, with GALT (lymphoid follicles, Peyer's patches, tonsils) developing between 11-20 weeks' gestation.
• These tissues are inactive until after birth, coinciding with the first antigenic challenges.
• Complete secretory immunity is achieved postnatally, with breastfeeding significantly contributing to immune development and maturation through its anti-infective and immunomodulatory properties.

Impact:

• Understanding the developmental timeline of mucosal immunity is crucial for identifying critical windows for intervention.
• Highlights the importance of breastfeeding in establishing robust infant secretory immunity and long-term mucosal health.
• Provides insights into the interplay between genetics and environment in shaping immune system maturation.