Lactic acid bacteria immune response

The mechanisms by which probiotics (and prebiotics) produce beneficial effects on the gut have not yet been fully elucidated. However, at least three mechanisms of action have been proposed (i) antibacterial agents produced by probiotic organisms may have an inhibitory effect on pathogenic microbes (ii) immune responses may be enhanced to suppress potential pathogens and (iii) competition in the gut epithelium may allow lactic acid bacteria and bifidobacteria to supplant pathogenic organisms. 

Perdigon, G., Nader de Macias, M.E., Roux, M.E., and de Ruiz Holdaga, A.A.P. 1990. The oral administration of lactic acid bacteria increase the mucosal immunity in response to enteropatho-gens. J. Food Prot. 53, 404—410. 

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