Description:
<jats:p>Fish oil supplementation during pregnancy has been associated with lower levels of cord blood IL-13, suggesting that the administration of<jats:italic>n</jats:italic>-3 fatty acids may attenuate the development of allergic disease. The present study aimed to investigate the mechanism by which<jats:italic>n</jats:italic>-3 fatty acid administration influences the production of IL-13. Pregnant BALB/c mice were fed nutritionally complete high-fat diets (15 %, w/w) with an<jats:italic>n</jats:italic>-3 fatty acid-enriched (DHA 1 %, w/w) or control diet (0 % DHA) immediately following delivery. Pups were exposed during suckling and weaned to the maternal diet for the remainder of the study. The production of IL-13, IL-4, IL-10 and interferon-γ from the splenocytes of ovalbumin (ova)-sensitised animals was assessed following<jats:italic>in vitro</jats:italic>ova stimulation or unstimulated conditions. Human T helper type 2 (Th2) cells were mitogen-stimulated in the presence or absence of DHA (10 μ<jats:sc>m</jats:sc>) and assessed for IL-13 and IL-4 expression using intracellular flow cytometry. The influence on transcriptional activation was studied using a human IL-13 promoter reporter construct and electromobility shift assay. Ova-activated splenocytes from DHA-fed mice produced less IL-13 (57·2 (<jats:sc>se</jats:sc>21·7) pg/ml) and IL-4 (7·33 (<jats:sc>se</jats:sc>3·4) pg/ml) compared with cells from the animals fed the control diet (161·5 (<jats:sc>se</jats:sc>45·0),<jats:italic>P</jats:italic>< 0·05; 33·2 (<jats:sc>se</jats:sc>11·8),<jats:italic>P</jats:italic>< 0·05).<jats:italic>In vitro</jats:italic>, DHA inhibited the expression of IL-13 protein from human Th2 cells as well as transcriptional activation and binding of the transcription factors cyclic AMP response element binding and activating transcription factor 2 to the human IL-13 promoter. These data indicate the potential of<jats:italic>n</jats:italic>-3 fatty acids to attenuate IL-13 expression, and suggest that they may subsequently reduce allergic sensitisation and the development of allergic disease.</jats:p>