Probiotic bacteria are shown to promote the endogeneous host defense mechanisms. In addition to the stabilization of the gut microflora, probiotics have been shown to enhance humoral immune responses and thereby promote the intestine’s immunologic barrier.
Moreover, probiotics modulate the host’s immune responses to harmful antigens with a potential to down-regulate hypersensitivity reactions. Probiotics also increase immunoglobulin A (IgA) and modulate cytokine production by mononuclear cells.