Veterinary Immunology and Immunopathology 148 (2012) 110–115 Contents lists available at ScienceDirect Veterinary Immunology and Immunopathology j o ur nal ho me p age: w ww.elsevier.com/locate/vetimm Research paper Practical immunoregulation: Neonatal immune response variation and prophylaxis of experimental food allergy in pigs Bruce N. Wilkie ∗ , Prithy Rupa, Julie Schmied Department of Pathobiology, Ontario Veterinary College, University of Guelph, Guelph, ON, Canada N1G2W1 a r t i c l e i n f o Keywords: Pig Immune response Neonatal Variation Environment Allergy prevention a b s t r a c t The importance of environment in immune response is identified and the increase in preva- lence of allergic, autoimmune and chronic inflammatory diseases reviewed. In particular, altered opportunity to acquire evolutionarily anticipated commensal microbiota is associ- ated through the “hygiene hypothesis” with defective developmental and response signals to the innate and adaptive immune systems. Evidence of the detrimental effects of such environments is reviewed as is evidence for remediation using controlled exposure to bac- teria or their active components such as LPS or peptidoglycan ligands for TLR and NOD-like receptors. Occurrence of major environmentally associated changes in porcine immune response phenotype are described. The prophylactic effects of heat-killed Escherichia coli given intramuscularly or of oral Lactococcus lactis on experimental ovomucoid-induced allergy in piglets are described in the context of altered immune response bias favouring reduced type-2 phenotypes. The high frequency of clinical tolerance to developing allergic signs even in the face of classical sensitization indicates possible function in this pig model of regulatory effectors such as Treg cells. © 2011 Elsevier B.V. All rights reserved. 1. Introduction Since innate and acquired immune response (IR) are integrated in mediating much of host adaptation to adverse environments they are a logical target in pur- suit of alterative health-management methods for animals (Wilkie and Mallard, 1999). Interventions based on genetic approaches to improving general rather than agent and disease-specific IR and indirectly, health and productivity, require objectively and reproducibly measurable quan- titative trait phenotypes as correlates. Such approaches have allowed selection for high and low IR as unweighted, combined antibody and cell-mediated IR estimated breed- ing values, in which heritability of IR is approximately 20% (Mallard et al., 1992, 1998). It is apparent that the ∗ Corresponding author. Tel.: +1 519 824 4120x54760; fax: +1 519 824 5930. E-mail address: bwilkie@uoguelph.ca (B.N. Wilkie). larger source of phenotypic variation is the environment such that profound negative or positive responses may arise from agent and disease non-specific environmental changes (Blaser and Falkow, 2009; Djuardi et al., 2009; Inman et al., 2010; Mulder et al., 2009). Amongst the large number of possible modern environmental variables that may influence IR and health, considerable attention has been given to early ontogeny of gastrointestinal com- mensal microbiota that under principles of “Darwinian medicine” (Rook, 2008) have evolved as necessary media- tors of host–environmental interactions. Alteration or loss of these anticipated environmental stimuli predisposes to human diseases reflecting dysregulation of the IR (allergy, asthma, autoimmunity) and others (obesity, type 2 dia- betes, esophageal adenocarcinoma, inflammatory bowel disease) (Rook, 2008; Blaser and Falkow, 2009). It has been suggested that man is unique amongst animals in ability to both change the environment to which the species has adapted in evolution and to adapt to adverse consequences of this change using cultural and technological means such 0165-2427/$ – see front matter © 2011 Elsevier B.V. All rights reserved. doi:10.1016/j.vetimm.2011.03.010