Abstract
The concept of immunological memory stipulates that past exposures shape present immune function. These exposures include not only specific antigens impacting adaptive immune memory but also conserved pathogen or danger associated molecular patterns that mold innate immune responses for prolonged periods of time. It should thus not come as a surprise that there is a vast range of external or environmental factors that impact immunity. The importance of environmental factors modulating immunity is most readily recognized in early life, a period of rapidly changing environments. We here summarize available data on the role of environment shaping immune development and from it derive an overarching hypothesis relating the underlying molecular mechanisms and evolutionary principles involved.
Highlights
The immune system is an organ that specializes in responding to environmental exposures
Despite contrary results for the protective effects of bacille Calmette-Guerin (BCG) against tuberculosis, vaccination is recommended to continue due to reduced infection from other mycobacteria as well as astonishing non-specific effects that have been recently noted in a randomized clinical trial in premature births in Guinea-Bissau
The cases above demonstrate that there can be short-term and lasting implications for lifelong health based on pre- and perinatal environmental exposures
Summary
The immune system is an organ that specializes in responding to environmental exposures. The purpose of this review is to amalgamate existing data into a cohesive vision on how early life environmental exposures leave a lasting impression on the human immune system, and how this impression can either have beneficial or potentially deleterious effects This vision incorporates the key principles of the developmental origin of health and diseases (DOHaD) hypothesis, the hygiene hypothesis as well insights from the field of developmental immunotoxicology (DIT) and posits that the sum of these mold immune memory. Newborns are more susceptible to several diseases when compared to adults; this appears to be at least partially due to a lack of acquired immune memory and differential regulation of innate immune responses [7, 8] This altered immunological priming is not maladaptive, www.frontiersin.org
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
