Journal of Dairy Research

Immunomodulatory consequences of oral administration of Lactobacillus rhamnosus strain GG in healthy volunteers

Michael Schultz a1c1, Hans-Jörg Linde a2, Norbert Lehn a2, Kurt Zimmermann a3, Johannes Grossmann a1, Werner Falk a1 and Jürgen Schölmerich a1
a1 Department of Internal Medicine I, University of Regensburg, Regensburg
a2 Institute of Clinical Microbiology and Hygiene, University of Regensburg, Regensburg
a3 Institute of Microecology, Herborn, Germany


Probiotic microorganisms, especially lactic acid bacteria, are effective in the treatment of infectious diarrhoeal diseases and experimental colitis. Although the mechanisms by which these organisms exert their anti-inflammatory effects are largely unknown, immunomodulating effects are suggested. The objective of this study was to examine the effect of a 5-week oral administration of Lactobacillus rhamnosus subspecies GG (Lb. GG) on the cellular immune response to intestinal microorganisms in ten healthy volunteers. Peripheral blood cells (PB) were stimulated with either ‘self’ or ‘non-self’ preparations of faecal samples and isolated Bacteroides fragilis group-organisms (Bfg) or Escherichia coli (Esch. coli), and pro- and anti-inflammatory cytokines (IL-10, IL-4, IL-6, IFN-γ, TNF-α) were measured in the culture supernatant. CD4+ T-lymphocyte activation was determined by measurement of intracellular ATP following lysis of the cells. The activational response of CD4+ T-lymphocytes towards isolated and heat-inactivated intestinal organisms was increased after the probiotic treatment. Additionally, TNF-α, IL-6 and in part IFN-γ cytokine secretion by PB cells following stimulation with whole stool preparations and single members of the flora was significantly decreased, whereas the IL-10 and in part IL-4 cytokine secretion was increased at the end of the study. In contrast, the activational response of CD4+ T-lymphocytes following stimulation with whole ‘non-self’ intestinal flora was higher than by ‘self’ intestinal flora, but both responses showed a trend towards a reduction at the end of the study. This study documents a direct effect by Lb. GG on the cellular immune system of healthy volunteers and offers a promising tool to investigate systemic immunomodulation due to oral administration of probiotic microorganisms.

(Received January 17 2002)
(Accepted June 5 2002)

Key Words: Probiotic therapy; immune system; Lactobacilli; Lactobacillus GG; intestinal microflora; human.

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