[Note: Lactobacillus plantarum is a species of lactic acid-producing bacteria that converts lactose & other sugars to lactic acid, used for example as a yogurt culture, and in probiotic supplements. NF KappaB is a protein that regulates genes responsible for immune activity in the gut.]
How do we acquire immune tolerance against food microorganisms and commensal [useful] bacteria that constitute the intestinal microbiota?
We investigated this by stimulating the immune system of adults with commensal Lactobacillus plantarum bacteria. We studied the in vivo human responses to L. plantarum in a randomized double-blind placebo-controlled cross-over study.
Healthy adults ingested preparations of living and heat-killed L. plantarum bacteria. Biopsies were taken from the intestinal duodenal mucosa, and altered expression profiles were analyzed using whole-genome microarrays and by biological pathway reconstructions.
Expression profiles of human mucosa displayed striking differences in modulation of NF-kappaB-dependent pathways, notably after consumption of living L. plantarum bacteria in different growth phases.
Our in vivo study identified mucosal gene expression patterns and cellular pathways that correlated with the establishment of immune tolerance in healthy adults.
Source: Proceedings of the National Academy of Sciences, Feb 3, 2009. PMID: 19190178, by van Baarlen P, Troost FJ, van Hemert S, van der Meer C, de Vos WM, de Groot PJ, Hooiveld GJ, Brummer RJ, Kleerebezem M. Top Institute Food and Nutrition, Laboratory of Microbiology; Laboratory of Agrotechnology and Food Sciences, Wageningen University, Wageningen, The Netherlands. [E-mail: