Postbiotic effects elicited by heat-inactivated Lacticaseibacillus rhamnosus GG against cow's milk allergy in human cells.

LGGp exposure resulted in activation of regulatory T cells (Tregs) in PBMCs from IgE-mediated CMA children stimulated with beta-lactoglobulin.

• PBMCs were collected from 6 IgE-mediated CMA children (all Caucasian, mean age 31.2 months).
• Tregs number was assessed by flow cytometry.
• Cells were stimulated with beta-lactoglobulin (BLG) in the absence or presence of LGGp.
• Tregs activation was observed as a beneficial immunomodulatory effect of LGGp.

LGGp exposure resulted in beneficial modulation of cytokine production in PBMCs from CMA patients stimulated with BLG.

• IL-4, IL-5, IL-13, and IL-10 production was assessed by ELISA.
• Growth factors and cytokines modulating interleukin production were assessed by RT-PCR.
• Modulation of cytokine production was described as beneficial in the context of immune tolerance.
• The cytokine profile changes were observed in PBMCs from 6 CMA children.

LGGp demonstrated beneficial effects on all measured biomarkers of gut barrier integrity in a Caco-2 cell-based experimental model.

• Gut barrier integrity was evaluated using a Caco-2 cells-based experimental model.
• Transepithelial electrical resistance (TEER) was measured as a marker of barrier integrity.
• Tight junction proteins, Mucin-2 (Muc-2), and lactase expression were assessed.
• FITC dextran permeability was measured to assess paracellular permeability.
• LGGp showed beneficial effects across all these biomarkers of gut barrier integrity.

LGGp modulated several immune tolerance mechanisms, paralleling immunomodulatory actions previously described for the live probiotic LGG in CMA.

• The probiotic LGG was noted to elicit immunomodulatory actions facilitating immune tolerance acquisition in children with CMA.
• LGGp (heat-inactivated LGG) was investigated as an emerging postbiotic form.
• Effects on Tregs activation and cytokine modulation were observed in parallel with gut barrier improvements.
• The findings suggest LGGp 'modulating several immune tolerance mechanisms, could be a promising therapeutic strategy against CMA.'