Lactic acid bacteria and probiotic organisms induce different cytokine profile and regulatory T cells mechanisms R. Ashraf a , T. Vasiljevic a , S.L. Day b , S.C. Smith c , O.N. Donkor a, * a Advanced Food Systems Research Unit, College of Health Science and Biomedicine, Victoria University, Werribee Campus, P.O. Box 14428, Melbourne, Vic 8001, Australia b Burnet Institute, Centre for Immunology, Melbourne, Vic 3004, Australia c School of Exercise and Nutrition Sciences, Deakin University, Vic 3125, Australia ARTICLE INFO Article history: Received 27 March 2013 Received in revised form 12 November 2013 Accepted 18 November 2013 Available online xxxx Keywords: Probiotics Lactic acid bacteria Cytokines Immuno-modulation CD4 + CD25 + FoxP3 + regulatory T cells ABSTRACT Immuno-modulatory effects of seventeen lactic acid bacteria (LAB) and probiotic strains were assessed following stimulation with peripheral blood mononuclear cells. Pro- and anti-inflammatory cytokines including interleukin (IL)-2, IL-4, IL-10, IL-12 p70, interferon (IFN)-c, tumor necrosis factor (TNF)-a and transforming growth factor (TGF)-b measured at different time points shows that all strains stimulated significant cytokines in varying concentrations and strain specific manner. Overall, TNF-a, IFN-c, IL-10 and TGF-b were stimulated at high concentrations where Lactobacillus casei 290 and Streptococcus thermophi- lus M5 stimulated TNF-a and IFN-c and Bifidobacterium strains stimulated maximum levels of IL-10 and TGF-b respectively. A significant increase in CD3 + CD4 + CD25 + and Treg popula- tion was observed where S. thermophilus M5 and 1342, B. animalis subsp. lactis BB12 and L. casei 290 showed seven-fold increase in FoxP3 expression. The study suggests that LAB and probiotics strains differ in their immuno-modulatory responses and functions, which necessitates their careful selection and characterization before applications. Crown Copyright Ó 2013 Published by Elsevier Ltd. All rights reserved. 1. Introduction The human microbiota is composed of approximately 10 14 bacterial cells, which is 10 times greater than the number of cells present in the human body. The gastrointestinal tract (GIT) is the most heavily colonized organ in the human body, where the colon itself is suggested to entail 70% of all the col- onizing microbes (Ley, Peterson, & Gordon, 2006). The surface area and nutritional abundance makes the GIT the preferred site of colonization. The human gut contains 500–1000 spe- cies however, analysis involving multiple subjects has re- ported over 35,000 bacterial species as the collective human gut microbiota (Sekirov, Russell, Antunes, & Finlay, 2010). Lactic acid bacteria (LAB) including genera lactobacilli, bifido- bacteria and enterococci are the most well-known and found abundantly in the intestinal tract especially in the lower small intestine and colon. Being predominant members of the community, LAB are commonly used in the manufacture of fermented dairy prod- ucts. Also majority of these species qualifies as ‘probiotics’ where the prime species include Lactobacillus acidophilus, Bifido- bacterium spp., and L. casei. Moreover, Streptococcus thermophilus along with L. delbrueckii subsp. bulgaricus, Lc. lactis and/or L. helveticus have also great economic importance and are frequently used as starters in production of cheese and fermented dairy products. Probiotic bacteria offer 1756-4646/$ - see front matter Crown Copyright Ó 2013 Published by Elsevier Ltd. All rights reserved. http://dx.doi.org/10.1016/j.jff.2013.11.006 * Corresponding author. Tel.: +61 3 9919 8059; fax: +61 3 9919 8284. E-mail address: Osaana.Donkor@vu.edu.au (O.N. Donkor). JOURNAL OF FUNCTIONAL FOODS xxx (2013) xxx – xxx Available at www.sciencedirect.com ScienceDirect journal homepage: www.elsevier.com/locate/jff Please cite this article in press as: Ashraf, R. et al., Lactic acid bacteria and probiotic organisms induce different cytokine profile and regulatory T cells mechanisms, Journal of Functional Foods (2013), http://dx.doi.org/10.1016/j.jff.2013.11.006