A mixture of two strains from

two different lactobacilli species (a combination of a high IL-10- and a GSK-3 beta phosphorylation high IL-12-inducing strain) was included in this study, but no clear synergistic effects were observed when compared with the individual strains. Although synergism is not always observed, some multispecies probiotic mixtures could expand the capacity for immunological modulation beyond that of the individual strains and might be effective in their immunomodulatory activity in selected patients (Timmerman et al., 2007; Niers et al., 2009; Kim et al., 2010; Lavasani et al., 2010). Summarizing the differential cytokine production profiles of the tested strains, it was observed that specific strains

selected on their IL-10-inducing properties, could be further grouped by their cytokine activity profile based on IFN-γ-inducing properties. The first group (represented by strains B1836, B2261, the mixture of B2261 and B633, B633 alone and CBI 118) induced a stronger proinflammatory TNF-α response, had a better inducing capacity of the Th1 compartment and showed a better inhibition of the Th2 cell compartment compared with the other group (represented by strains B1836 and B223), and might therefore be more appropriate candidate probiotics for allergic patients. A remarkable finding was the consistent inhibition of proliferation of hPBMC stimulated for 4 days with αCD3/αCD28 in the presence of all the applied bacterial strains with the most profound and significant inhibition by strain B633 in all seven allergic donors tested. ABT-199 concentration However, addition of strain Oxymatrine B633 did not impair cytokine induction, which strengthens the notion that various aspects of immunomodulation can be unique for a strain and that large species and strain differences exist in effects on inhibiting allergic inflammation, repression of hypersensitivity reactions and clinical symptoms of allergy (Medina et al., 2007; Isolauri & Salminen, 2008; Vissers et al.,

2010). These data support the notion that the probiotic potential of lactic acid bacteria as antiallergic compounds is strain specific and largely variable already in vitro as is also reported upon in vivo use in randomized double-blind, placebo-controlled clinical studies (Isolauri & Salminen, 2008; Kalliomaki et al., 2010). Donors with a documented pollen allergy were recruited outside the pollen season, resulting in a low frequency of allergen-specific T cells that can be as low as 1 per 20 000 cells (Gabrielsson et al., 1997), consequently resulting in a low response to the Bet v 1 allergen. Enrichment of the allergen-specific T cells or the use of allergen-specific T-cell clones would be necessary to study potential modulatory effects of bacterial strains under allergen-specific culture conditions (Ebner et al., 1995; Bohle, 2007).