CONICET | Buscador de Institutos y Recursos Humanos

Our previous research showed that commercial probiotic fermented milk (PFM) intake mitigates respiratory allergy development to ovalbumin (OVA) in adult mice (6-weeks-old) increasing specific IgG2a and IFN-γ instead of IgE. Aim: to determine if this PFM exerts a protective effect when allergy model is induced 5 days after weaning and whether the mechanisms involved are similar to those previously reported. Before inducing allergy, a group of 21-days-old BALB/c mice were given PFM for 10 days to analyse the impact on the intestinal epithelial cells (IEC?s) activation. Two more groups were administered with PFM for 5 days and then sensitised with OVA, only one group continued taking PFM until the end of the experience. Sensitization scheme: 3 OVA injections 1% in PBS plus 7 days with OVA aerosols exposure and a re-stimulus 15 days later. The content of specific-IgE, IgG, total-secretory-IgA and Th1/Th2 balance in serum, bronchoalveolar- lavage (BAL) and gut was studied measured at 7 and 15 days post-sensitization (dPS) and 2 days post-re-stimulus (dPR). Treg cells in lungs were also analysedquantified. Results were compared with normal and sensitized controls. PFM induced a mild activation of IEC?s increasing mMonocyte chemoattractant protein-1 (MCP-1 o CCL2) and IL-6IL6 production. In sensitised mice PFM controlled the response inducing IgG instead of IgE at 7 and 15-dPS and 2dPR (60 days old). Th1-balance (IFN-γ) was favoured by PFM in lungs at 7 dPS with low levels of IL-10IL10 released to regulate the response. Total-S-IgA increased in lungs and gut; however, PFM intake did not affect Treg cells in lungs. PFM keeps a controlled stimulation of immune cells involved in Th1 response favouring IgG at the respiratory mucosal site. Although the effect was not as strong as reported previously, PFM promoted maturation and activation of the gut immune cells maintaining intestinal homeostasis and lungs immune response