A comparison of cell mediators and serum cytokines transcript expression between male and female mice infected with Mycobacterium avium subspecies paratuberculosis and/or consuming probiotics.

The gut immune system is complex, and dysregulation leads to a number of disorders including inflammatory bowel syndrome and (in livestock) Johne's disease. Previous work has demonstrated that males and females respond differently to treatment with pathologic and probiotic microorganisms, suggesting that a 'one-size-fits-all' approach to treat GIT inflammation may be inadequate. While we had observed significant differences between males and females in terms of cytokine production, it remains unclear how these changes occur. To better understand the mechanisms, transcript expression of genes important to gut immunoregulation were monitored from male and female BALB/c mice consuming the probiotic Lactobacillus animalis (1 × 10(6) CFU g(-1) ) and infected with the gut pathogen, Mycobacterium avium subspecies paratuberculosis (1 × 10(7) CFU). Expression of transcripts analyzed included those important to the immune system, intestinal cell differentiation, and/or regulation. Males generally displayed increased expression of Th 2 and B-cell mediators, and females showed repressed cytokine expression after MAP infection (IL-6, TNF-α, IL-1 among others). Additionally, regulation of pro-inflammatory mediators in female mice consuming probiotics suggests females responded positively to L. animalis when compared to males. Therefore, we speculate that studying mechanistic changes associated with sex and immunoregulation in gastrointestinal tissues could further elucidate host response to microorganisms.

Effects of the probiotic Lactobacillus animalis in murine Mycobacterium avium subspecies paratuberculosis infection.

BACKGROUND: MAP is a suspected zoonotic pathogen and the causative agent of Johne's Disease in cattle and other ruminant animals. With over $1 billion dollars in loss to the dairy industry due to Johne's Disease, efforts to eliminate or reduce MAP from cattle are of importance. The purpose of this study was to determine if daily intake of probiotics could eliminate or reduce Johne's Disease associated symptoms and pathogenesis by MAP. Post infection, animals are often asymptomatic carriers with limited shedding of the pathogen, proving early detection to be difficult. Disease and symptoms often appear 3-4 years after infection with antibiotic treatment proving ineffective. Symptoms include chronic gastrointestinal inflammation leading to severe weight-loss from poor feed and water intake cause a wasting disease. These symptoms are similar to those found in individuals with Crohn's Disease (CD); MAP has been implicated by not proven to be the causative agent of CD. Probiotics administered to livestock animals, including dairy and beef cattle have demonstrated improvements in cattle performance and health. Our objectives included determining the benefits of Lactobacillus animalis (strain name: NP-51) in MAP infected BALB/c mice by evaluating systemic and gastrointestinal response by the host and gut microbiota. Male and female animals were fed 1×106 CFU/g probiotics in sterile, powdered mouse chow daily and infected with 1 × 107 CFU/ml MAP and compared to controls. Animals were evaluated for 180 days to assess acute and chronic stages of disease, with sample collection from animals every 45 days. MAP concentrations from liver and intestinal tissues were examined using real time-PCR methods and the expression of key inflammatory markers were measured during MAP infection (interferon-gamma [IFN-Υ], Interleukin-1α, IL-12, IL-10, IL-6, and Tumor necrosis factor alpha [TNF-α]). RESULTS: Our results demonstrate administration of probiotics reduces production of IFN-Υ and IL-6 while increasing TNF-α and IL-17 in chronic disease; healthful immune responses that reduce chronic inflammation associated to MAP infection. CONCLUSIONS: We observed that the immune system's response in the presence of probiotics to MAP contributes towards host health by influencing the activity of the immune system and gut microbial populations.