Adhesive and chemokine stimulatory properties of potentially probiotic Lactobacillus strains

Five Lactobacillus plantarum strains and two Lactobacillus johnsonii strains, stemming either from African traditionally fermented milk products or children's feces, were investigated for probiotic properties in vitro. The relationship between the hydrophobic-hydrophilic cell surface and adhesion ability to HT29 intestinal epithelial cells was investigated, and results indicated that especially the L johnsonii strains, which exhibited both hydrophobic and hydrophilic surface characteristics, adhered well to HT29 cells. Four L. plantarum and two L. johnsonii strains showed high adherence to HT29 cells, generally higher than that of the probiotic control strain Lactobacillus rhamnosus GG. Most strains with high adhesion ability also showed high autoaggregation ability. The two L. johnsonii strains coaggregated well with the intestinal pathogens Listeria monocytogenes Scott A, Staphylococcus aureus ATCC 25923, Escherichia coli ATCC 25922, and Salmonella enterica serovar Typhimurium ATCC 14028. The L plantarum BFE 1685 and L. johnsonii 6128 strains furthermore inhibited the adhesion of at least two of these intestinal pathogens in coculture with HT29 cells in a strain-dependent way. These two potential probiotic strains also significantly increased interleukin-8 (IL-8) chemokine production by HT29 cells, although modulation of other cytokines, such as IL-1, IL-6, IL-10, monocyte chemoattractant protein-1 (MCP-1), tumor necrosis factor alpha (TNF-alpha), and transforming growth factor beta (TGF-beta), did not occur. Altogether, our results suggested that L. plantarum BFE 1685 and L. johnsonii BFE 6128 showed good adherence, coaggregated with pathogens, and stimulated chemokine production of intestinal epithelial cells, traits that may be considered promising for their development as probiotic strains.