Dietary Bifidobacterium lactis (HN019) Enhances Resistance to Oral Salmonella typhimurium Infection in Mice

Abstract

The ability of a newly identified probiotic lactic acid bacterial strain, Bifidobacterium lactis (HN019), to confer protection against Salmonella typhimurium was investigated in BALB/c mice. Feeding mice with B. lactis conferred a significant degree of protection against single or multiple oral challenge with virulent S. typhimurium, in comparison to control mice that did not receive B. lactis. Protection included a ten-fold increase in survival rate, significantly higher post-challenge food intake and weight gain, and reduced pathogen translocation to visceral tissues (spleen and liver). Furthermore, the degree of pathogen translocation showed a significant inverse correlation with splenic lymphocyte proliferative responses to mitogens, blood and peritoneal cell phagocytic activity and intestinal mucosal anti-S. typhimurium antibody titers in infected mice; all of these immune parameters were enhanced in mice fed B. lactis. Together, these results suggest that dietary B. lactis can provide a significant degree of protection against Salmonella infection by enhancing various parameters of immune function that are relevant to the immunological control of salmonellosis. Thus dietary supplementation with B. lactis provides a unique opportunity for developing immune-enhancing probiotic dairy food products with proven health benefits.

Enhancement of natural immune function by dietary consumption of Bifidobacterium lactis (HN019)

“…In particular, Bi®dobacterium lactis (strain HN019, DR10 TM ) has been shown to enhance phagocytic cell function and the production of interferongamma (IFNg) in laboratory animals, and to increase immune-mediated resistance in mice to challenge with a virulent strain of Salmonella typhimurium (Gill, 1998;Gill et al, 1999;Shu et al, 1999). In the present study, we report the immunomodulatory effects of dietary B. lactis HN019 in healthy elderly subjects.…”

“…Previous studies have indicated that dietary consumption of some strains of LAB can signi®cantly enhance host resistance to GI-tract infections, and subsequently reduce clinical recovery times Majamaa et al, 1995;Saxelin, 1997). The strain of B. lactis used here (HN019) has recently been shown to enhance phagocytic cell function and increase resistance in mice to infection with Salmonella typhimurium (Shu et al, 1999), further indicating that dietary consumption of probiotic LAB has the potential to offer signi®cant immune-mediated improvements in health.…”

Enhancing immunity by dietary consumption of a probiotic lactic acid bacterium (Bifidobacterium lactis HN019): optimization and definition of cellular immune responses

“…While it is dif®cult to correlate a proven health bene®t in humans with a measurable increase in immune function, there is some circumstantial evidence to support the case with probiotic LAB, since dietary consumption of live yoghurt cultures has been shown to reduce intestinal viral infections, and may also reduce tumour growth (Saavedra et al, 1994;Sawamura et al, 1994;Aso et al, 1995;Majamaa et al, 1995;Rafter, 1995). In previous studies, we have demonstrated that dietary consumption of B. lactis can enhance cellular immune function in mice (Gill, 1998;Gill et al, 2000) and that this enhancement correlates with increased resistance to intestinal infection with Salmonella typhimurium (Shu et al, 2000); there is therefore the promising possibility that enhancement of immune function by dietary consumption of B. lactis might also provide disease protection in humans, however this remains to be determined.…”

Oral Administration of Bifidobacterium bifidum G9-1 Suppresses Total and Antigen Specific Immunoglobulin E Production in Mice

“…2,3) Furthermore, several reports have revealed that these probiotics can act in helping to protect from intestinal infections, 4,5) alter immunostimulation 6) and decrease elevated serum levels of cholesterol 7,8) and glucose 8-10) on several animal models. There have been several recent reports on regulation of allergic antibody production.…”