CORK, Ireland—Data from a recent study show that anti-inflammatory benefits of Bifidobacterium infantis 35624, a probiotic bacterial strain of human origin, extend to the entire body might be useful in the treatment of autoimmune inflammatory conditions. The report is in the August issue of the Public Library of Science (PLoS) Pathogens.¹

“Inflammation is a major factor in a number of chronic disease affecting millions of people and can cause an unwanted impact on healthy tissue,” said lead investigator Liam O'Mahony, MD. “Past research has shown that the probiotic ...can positively impact the body's immune defense, and this most recent data suggest that its benefits are not restricted to the gastrointestinal tract.”

Probiotics, defined as “live microbial food ingredients that, when ingested in sufficient quantities, exert health benefits on the consumer,” have been studied for treatment of diarrhea and attenuation of antibiotic-associated gastrointestinal side effects.

B infantis 35624 was isolated from healthy human gastrointestinal tissue, cultured anaerobically for 48 hours, and administered as a freeze-dried powder reconstituted in water at about 1x10⁹ colony forming units/day/animal in the drinking water.

According to Dr. O'Mahony, previous study showed that the probiotic could modulate inflammatory responses in patients with irritable bowel syndrome. The current study examined the effect of a freeze-dried preparation of B infantis 35624 on regulatory T-cells (Treg) in mice subsequently infected with Salmonella typhimurium.

The researchers reported that mice that had received the probiotic showed dramatically increased numbers of Treg cells, which protected the mice from excessive inflammation during the course of infection. In vivo imaging showed that the probiotic-treated mice had “profound inhibition of infection and [lipopolysaccharide] induced NF-κB activity that preceded a reduction in S typhimurium numbers and murine sickness behavior scores.... In addition, pro-inflammatory cytokine secretion, T-cell proliferation, and dendritic cell costimulatory molecule expression were significantly reduced,” the researchers wrote.

Mice fed B infantis were protected from the effects of infection with S typhimurium. This protection was mediated by a significant increase in CD4+CD25+ T-cells, most of which also stained positive for the Treg transcription factor Foxp3.

“The deliberate consumption of one commensal organism, B infantis 35624 resulted in the induction of Treg cells [that] protected the host from excessive inflammation during the course of infection as evidenced by reduced pro-inflammatory cytokine production, reduced T-cell proliferation, reduced dendritic cell costimulatory molecule expression, and attenuation of NF-κB activation,” Dr. O'Mahony said.

The authors are affiliated with Alimentary Health Ltd, a multidepartmental university campus-based company at University College, Cork, Ireland, which also supported the study.

Reference

1. O'Mahoney C, Scully P, O'Mahony D, et al. Commensal-induced regulatory T cells mediate protection against pathogen-stimulated NF-κB activation. PLoS Pathog. 2008; 4(8):e1000112. http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=2474968.