Exposure of Children to Rural Lifestyle Factors Associated With Protection Against Allergies Induces an Anti-Neu5Gc Antibody Response.

Remo Frei,Caroline Roduit,Roger P. Lauener,Liam O'Mahony,Ruth Ferstl

doi:10.3389/fimmu.2019.01628

Abstract

Rural lifestyle has been shown to be highly protective against the development of allergies. Contact to farm-animals or pets and early-life consumption of milk products turned out to be important. These exposures provide contact to N-glycolylneuraminic acid (Neu5Gc), a sialic acid naturally expressed in mammalians but not in humans or microbes although both are able to incorporate exogenously provided Neu5Gc and induce thereby an anti-Neu5Gc antibody response. Farmers' children had elevated levels of anti-Neu5Gc antibodies associated with increased contact to Neu5Gc. Farm-related exposures that were associated with protection against allergies such as exposure to farm-animals or pets and consumption of milk were also associated with an antibody response to Neu5Gc in children. Exposure to cats was associated with increased anit-Neu5Gc IgG levels at different timepoints assessed between 1 year of age and school-age. Moreover, consumption of non-pasteurized milk in the first year of life was associated with increased anti-Neu5Gc IgG levels. Neu5Gc-providing exposures that were associated with protection against allergies were reflected in an elevated anti-Neu5Gc IgG level in children. Exposure to Neu5Gc was associated with anti-inflammation and protection of asthma development in children and mice without contribution of anti-Neu5Gc antibodies.

Highlights

The hygiene hypothesis was proposed after a lower risk of hay fever and atopic sensitization among children having more siblings was observed [2]
Detailed underpinning immunological mechanisms were not fully known, this was the first study showing an immunemodulatory, anti-inflammatory effect of Neu5Gc itself, which is in contrast to findings of xenograft rejection and tumor growth where anti-Neu5Gc antibodies were associated with a pro-inflammatory status [13,14,15,16,17,18,19]
Anti-Neu5Gc IgG levels were associated with rural environmental exposures reflecting protection against allergies and asthma (Table 1)

Summary

Introduction

Associated With Protection Against Allergies Induces an Anti-Neu5Gc Antibody Response. Farmers’ children had elevated levels of anti-Neu5Gc antibodies associated with increased contact to Neu5Gc. Farm-related exposures that were associated with protection against allergies such as exposure to farm-animals or pets and consumption of milk were associated with an antibody response to Neu5Gc in children.

Results

Conclusion