Immune modulation of blood leukocytes in humans by lactic acid bacteria: criteria for strain selection

Abstract

Lactic acid bacteria in food can transiently colonize the intestine and exert beneficial effects (probiotic). Survival during intestinal transit or adhesion to epithelium or both seem to be important for modifying the host's immune reactivity. Because Lactobacillus acidophilus strain La1 is adherent to enterocytes in vitro, we hypothesize that contact with immune cells may occur in vivo. However, Bifidobacterium bifidum strain Bb12, which shows high fecal colonization, is another potential immunomodulator. Twenty-eight volunteers were divided into two groups and given a fermented product containing one of the two strains. Lymphocyte subsets and leukocyte phagocytic activity were studied in blood. No modifications were detected in lymphocyte subsets. In contrast, phagocytosis of Escherichia coli ssp. was enhanced in both groups (P < 0.001 for both). Bacterial adhesion to enterocytes, fecal colonization, or both seem to be valuable selection criteria for immunomodulation. Antiinfective mechanisms of defense can be enhanced after ingestion of specific lactic acid bacteria strains.

A Randomised Controlled Trial of a Probiotic Lactobacillus Strain in Healthy Adults: Assessment of its Delivery, Transit and Influence on Microbial Flora and Enteric Immunity

“…In contrast, a systemic serologic immune response against the strain was not evident. Although increased granulocyte (but not monocyte) phagocytic activity was observed in subjects fed the U CC118 Rif strain in fermented but not in fresh milk, and a similar nding has previously been reported after consumption of L. acidophilus (34,35), the biological signi cance of this is unclear. It does, however, indicate an increased immune status, which is a concept frequently, associated with, and promoted by, the marketing of probiotics.…”

Lactobacillus acidophilus 74-2 and Bifidobacterium animalis subsp lactis DGCC 420 modulate unspecific cellular immune response in healthy adults

“…Indicating a stimulation of the immune system, these outcomes can be important for several population groups, for example elderly, stressed workers and children that are susceptible for infections. An enhancement of the immune system induced by probiotic bacteria can reduce duration and severity of infectious diseases (Schiffrin et al, 1997;Hatakka et al, 2001;Turchet et al, 2003). The expression of the specific cellular surface markers (CDs) remained unaffected through this study.…”

Probiotic properties of lactic acid bacteria isolated from traditionally fermented Xinjiang cheese

“…Some like Lactobacillus, Streptococcus, Pediococcus, and Enterococcus are cultivable and predominant microbes in fermented dairy products, and exert a positive role in human health following oral administration. They improve the balance of the microbial community in the intestine, confer protection against potential pathogenic bacteria, and prevent and/or cure intestinal diseases (Schiffrin et al, 1997;Gionchetti et al, 2000). These effects are mediated by production of antimicrobial metabolites such as organic acids (for example lactate, acetate, and butyrate), hydrogen peroxide, and bacteriocins, and competition with harmful bacteria for nutrients or adhesion receptors (Hudault et al, 1997;Fons et al, 2000).…”