title: Orally administered Lactobacillus rhamnosus modulates the respiratory immune response triggered by the viral pathogen-associated molecular pattern poly(I:C).
abstract: BACKGROUND
  Some studies have shown that probiotics, including Lactobacillus rhamnosus CRL1505, had the potential to beneficially modulate the outcome of certain bacterial and viral respiratory infections. However, these studies did not determine the mechanism(s) by which probiotics contribute to host defense against respiratory viruses.
  
  
  RESULTS
  In this work we demonstrated that orally administered Lactobacillus rhamnosus CRL1505 (Lr1505) was able to increase the levels of IFN-γ, IL-10 and IL-6 in the respiratory tract and the number of lung CD3(+)CD4(+)IFN-γ(+) T cells. To mimic the pro-inflammatory and physiopathological consecuences of RNA viral infections in the lung, we used an experimental model of lung inflammation based on the administration of the artificial viral pathogen-associated molecular pattern poly(I:C). Nasal administration of poly(I:C) to mice induced a marked impairment of lung function that was accompanied by the production of pro-inflammatory mediators and inflammatory cell recruitment into the airways. The preventive administration of Lr1505 reduced lung injuries and the production of TNF-α, IL-6, IL-8 and MCP-1 in the respiratory tract after the challenge with poly(I:C). Moreover, Lr1505 induced a significant increase in lung and serum IL-10. We also observed that Lr1505 was able to increase respiratory IFN-γ levels and the number of lung CD3(+)CD4(+)IFN-γ(+) T cells after poly(I:C) challenge. Moreover, higher numbers of both CD103(+) and CD11b(high) dendritic cells and increased expression of MHC-II, IL-12 and IFN-γ in these cell populations were found in lungs of Lr1505-treated mice. Therefore, Lr1505 treatment would beneficially regulate the balance between pro-inflammatory mediators and IL-10, allowing an effective inflammatory response against infection and avoiding tissue damage.
  
  
  CONCLUSIONS
  Results showed that Lr1505 would induce a mobilization of cells from intestine and changes in cytokine profile that would be able to beneficially modulate the respiratory mucosal immunity. Although deeper studies are needed using challenges with respiratory viruses, the results in this study suggest that Lr1505, a potent inducer of antiviral cytokines, may be useful as a prophylactic agent to control respiratory virus infection.
authors.affiliation: Laboratory of Clinical and Experimental Biochemistry, Reference Centre for Lactobacilli (CERELA-CONICET), Tucuman, Argentina. jcvillena@cerela.org.ar
authors.forename: Julio
authors.initials: J
authors.lastname: Villena
authors.forename: Eriko
authors.initials: E
authors.lastname: Chiba
authors.forename: Yohsuke
authors.initials: Y
authors.lastname: Tomosada
authors.forename: Susana
authors.initials: S
authors.lastname: Salva
authors.forename: Gabriela
authors.initials: G
authors.lastname: Marranzino
authors.forename: Haruki
authors.initials: H
authors.lastname: Kitazawa
authors.forename: Susana
authors.initials: S
authors.lastname: Alvarez
mesh_terms: D000284:Administration, Oral; D000818:Animals; D015496:CD4-Positive T-Lymphocytes / Q000276:immunology* / Q000382:microbiology / Q000821:virology; D002465:Cell Movement; D002478:Cells, Cultured; D016207:Cytokines / Q000378:metabolism; D003713:Dendritic Cells / Q000276:immunology / Q000382:microbiology / Q000821:virology; D006801:Humans; D056747:Immunomodulation; D018836:Inflammation Mediators / Q000378:metabolism; D052201:Lacticaseibacillus rhamnosus; D008297:Male; D051379:Mice; D008807:Mice, Inbred BALB C; D011070:Poly I-C / Q000008:administration & dosage; D019936:Probiotics / Q000008:administration & dosage*; D012327:RNA Virus Infections / Q000276:immunology*; D012137:Respiratory System / Q000473:pathology
chemical_list: D016207:Cytokines; D018836:Inflammation Mediators; D011070:Poly I-C