Immunostimulatory effect of faecal Bifidobacterium species of breast-fed and formula-fed infants in a peripheral blood mononuclear cell/Caco-2 co-culture system

Bifidobacterium spp. typical of the human intestinal microbiota are believed to influence the balance of immune responses in the intestinal mucosa. The aim of the present study was to investigate the effect of different bifidobacterial species and their mixtures in in vitro experiments with peripheral blood mononuclear cells (PBMC) and Caco-2 cells. Bifidobacterium adolescentis, B. angulatum, B. breve, B. catenulatum, B. infantis, B. longum and two combinations of these bifidobacteria simulating the species composition found in faecal samples from breast-fed (BF) and formula-fed (FF) infants were used. The levels of several cytokines were measured by direct stimulation of PBMC and by stimulation of a Caco-2/PBMC co-culture with bifidobacteria. B. catenulatum and B. breve were the strongest enhancers of interferon-γ (IFN-γ) production by direct stimulation of PBMC. B. longum was the highest inducer of IL-10 and the lowest TNF-α stimulus. In the Caco-2/PBMC system, B. breve was the highest inducer of IL-8 production by Caco-2 cells, significantly different from B. infantis, B. adolescentis and the FF mixture (P?