[Screening of beta-lactoglobulin allergy-modulating lactobacilli strains using in vitro-in vivo correlation]

We investigated the correlation between the in vitro immune profiling of 5 lactobacilli strains and their in vivo protective effect in a mouse beta-lactoglobulin (BLG) allergy model for selecting the candidate strains with potential anti-allergy activity.

In vitro immunomodulation was assessed by measuring interleukin (IL)-4 and interferon gamma (IFN-gamma) release by primary lymphocytes stimulated with 5 active/heat-killed lactobacilli. A mice model of beta-lactoglobulin allergy was then used to evaluate the alleviating allergy capacity of the same set of strains. The rats were randomly divided into blank group, BLG allergy group and different lactobacilli strains group. The total IgE and BLG-specific IgE contents in the serum of rats were measured with ELISA. Splenic lymphocytes were isolated and cultured in vitro, the levels of Thl/Th2 type cytokine were detected by ELISA.

Protection of BLG-induced allergy was strain-specific. The strains displaying an in vitro capacity to induce higher levels of the Thl type cytokine (IFN-gamma) and lower levels of the Th2 type cytokine (IL-4), significantly decreased the levels of total IgE and BLG-IgE in allergic rat serum (P<0.05). In contrast, strains leading to a low IFN-gamma/IL-4 cytokine ratio could not significantly attenuate allergic symptoms.

We could predict the in vivo protective capacity of the studied lactobacilli strains based on the cytokine profile established in vitro. Oral consumption of specific strain may be effective in preventing and alleviating BLG allergic symptoms by the improvement of the Th1/Th2 cell balance toward Th1 dominance, and the inhibition of IgE production.