engleski

S-layer proteins of probiotics as living drugs

Surface (S-) layers composed of identical (glyco)protein subunits are macromolecular structures non-covalently linked to the bacterial surface. Among numerous lactic acid bacteria (LAB) species only several Lactobacillus strains possess S- proteins. S- proteins are reported to have potential for biotechnological applications due to their structural regularity and unique self-assembling. In fact, important probiotic traits of Lactobacillus strains, adhesion, pathogen exclusion and immunomodulation are related with the occurrence of S-layers. Among 200 autochthonous LAB strains characterised as probiotic or starter cultures in the Collection of Lactic Acid Bacteria in our laboratory only six S-layer carrying Lactobacillus strains: four Lb. brevis, one Lb. paraplantarum and one Lb. helveticus, were selected. After S-proteins´ characterization, their role in auto- and coaggregation, survival in simulated gastrointestinal tract conditions, adhesion to extracellular matrix proteins and intestinal epithelial cells, pathogen exclusion as well as protective coat´s role during production and application of active dried probiotic preparations was investigated. Especially role in immunomodulation activity of Lactobacillus strains is studied in order to establish their possible development as mucosal vaccines. Results suggest that certain probiotic activities of Lactobacillus strains are mediated by S-layer proteins where immunomodulating capacity of S-layer expressing Lactobacillus strains varied from one bacterial strain to another.

adhesion; functionality; immunomodulation; Lactobacillus; S-layer surface proteins

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