Ontogeny of mucosal immunity--environmental and behavioral influences

Since mucosal surfaces represent the interface between the host and the environment and are the most common portal of pathogen entry, early development of functional mucosal immune defense is essential for survival. The development of mucosal immune function is profoundly influenced by maternal, environmental, and behavioral factors and although the impact of these is greatest during the prenatal and immediately postnatal periods, their influence extends beyond this period and patterns of development in postnatal life determine many of the immune outcomes in later life. This review will correlate information regarding age-related changes occurring in mucosal-associated lymphoid tissue from a variety of animal models and in humans and will explore how the interactions which exist between the immune and neuroendocrine systems orchestrate these effects. In particular the role of prenatal and postnatal stressors, feeding patterns, nutritional factors, infections, and exposure to allergens and toxins are addressed. A clear understanding of the way in which these factors interact to influence development and control of mucosal immune function will assist in the design of neonatal vaccination and disease management strategies.