Abstract # 1763 Investigating the Influence of environment and psychological state on the immune response: Developing a PNI toolkit

Abstract

Studies have recently demonstrated the immune system to significantly more plastic than previously believed. Multiple external factors have been shown to influence the immune response including alterations to the host’s external environment and psychological status. This study aimed to investigate this influence utilising classic models of inflammatory disease. Following a two week period of environmental enrichment subjects were challenged with either a model of acute inflammation or bacterial sepsis; zymosan inducedperitonitis (ZIP) and caecal ligation and puncture (CLP). The results of the ZIP model revealed a markedly altered immune response, typified by heightened cell migration to and maturation at the point of immune insult. In CLP we observed analogous results,accompanied by a significant inhibition of systemic bacterial spread in enriched animals. Micro-array analysis supported these findings, revealing the increased expression of immune-modulatory genes associated with a heightened immune response. We further discovered these changes to persist ex vivo , identifying macrophages isolated from enriched animals to possess a significantly enhanced phagocytic capacity alongside an unchanged profile of cytokine release. These results demonstrate environmental enrichment has an enhancing effect on the murine immune response: Upregulating immune-protective gene expression and heightening both leukocyte number and function to improve clearance of systemic bacterial infection. We also believe these results will aid in establishing a series of immunological models that could assess the effects of environment and psychological state on the active immune response.