Nutritional immunity : a new concept for animal nutritionists

Dr Kevin Waldron, from Newcastle University (UK), presented the process of nutritional immunity applied to metals, at host/pathogen interface. Transition metals are cofactors for many proteins that are essential for life, and their concentration within cells is carefully maintained to avoid both deficiency and toxicity. To defend against bacterial pathogens, vertebrate immune proteins sequester metals, in particular zinc, iron, and manganese, as a strategy to limit bacterial acquisition of these necessary nutrients. In response, bacteria have evolved strategies to access metals and counteract this host defense. This explains a complex interplay between nutrition, host and microbiota. In presence of pathogens, neutrophil effector calprotectin (CP) plays a central role, restricting Mn availability in tissues and Zn availability in the inflamed gut.