The probiotic paradox state both live and dead cells in probiotic products can generate beneficial biological responses and the term parabiotics was selected to indicate the inactivated dead probiotics cells. Enterocooci are lactic acid bacteria (LAB) and because of their tolerance to salts and acids, and the production of antimicrobial bacteriocins were traditionally accept as probiotic and involved in the preparation of fermented foods. However concerns over the safety of Enterococcus spp. as a probiotic have been increasingly raised todays. In the current study we used the Enterococcus sp. parabiotic to manage the lung inflammation in mice following the administration of viral mimic Poly inosinic:polycytidylic acid (poly I:C). Enterococcus cells (that was previously obtained from the traditional pickles) were inactivated by heat pre-treatment at 80 ºC for 30 min. Male BALB/c mice, 8-12 weeks-old, were intranasally administered 20 µl of Enterococcus parabiotic (10⁸ CFU/mL) for 5 consecutive days under inhalation anesthesia with isoflurane. Mice received three doses of 20 µl poly (I:C) (1 mg/ml) on days 5-7 and were euthanized on day 10 i.e. 24 h after the last intranasal treatment. Control animals received PBS instead of parabiotic. The immune-modulatory activity of Enterococcus parabiotic was determined based on the measure of cytokine levels in the BALF (bronchoalveolar tissue lavage fluid), lung histology, and the lung wet-to-dry (W/D) weight ratio. The quantitative analysis of pro-inflammatory cytokines revealed that TNF-α, IL-1β and IL-6 were significantly reduced by 3.1, 4.2, and 4.4 folds in the mice received inactivated Enterococcus (P<0.05). The lung tissue samples from the parabiotic treatment group displayed typical histology of normal lungs with thin alveolar walls and absence of intraalveolar edema. Compared with the control group (6.7 ± 0.15), the wet/dry weight ratios of lung tissues in the parabiotic group (5.7 ± 0.13) were significantly decreased. Our findings indicate that Enterococcus parabiotic modulates the inflammatory response in bronchial epithelial cells and it can be a useful tool to manage the acute respiratory distress syndrome (ARDS).

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