COMPARATIVE in vivo AND in vitro STUDY OF IMMUNOMODULATORY PROPERTIES OF PEPTIDOGLYCANS OBTAINED FROM DIFFERENT Lactobacillus STRAINS

YANINA KOLLING; MARIANA FERRERO; SUSANA SALVA; JORGE VILLENA; PABLO BALDI; SUSANA ALVAREZ

San Miguel de Tucumán

Simposio; V Simposio Internacional de Bacterias Lácticas; 2016

The use of non-viable lactic acidbacteria and their cellular fractions are excellent alternatives to stimulateimmunity in immunocompromised hosts, in which viable microorganisms couldinvolve a health risk. The aim of this work was to compare the immunomodulatoryproperties ofpeptidoglycan obtained from the immunobioticLactobacillus rhamnosus CRL1505 (Pg05), with the peptidoglycansobtained from the non-probioticL.rhamnosus CRL534 (Pg534) and from the probiotic L. plantarum CRL1506 (Pg06) by invitro and in vivo studies. At thefirst time, we study the effect on the innate immune response inimmunocompromised-malnourished mice. Weaned mice were malnourished with aprotein-free diet for 21 days and then received balanced diet during 7d (BDgroup) or were fed BD 7d with nasal supplementation of Pg05, Pg06 or Pg534during the last 2d. On d8 wereinfected all experimental groupswith Streptococcus pneumoniae(Sp)and theresistance to the infection and innate immune response were studied. Lung andblood Sp counts in Pg06 and Pg534 groups were similar to the BD group while wasnot detected the pathogen in samples of Pg05-treated mice. Moreover, lungtissue injuries in Pg05 were significantly lower when compared to the othergroups. Pneumococcal infection increased CD45+Gr-1+neutrophils, CD45+F4/80+CD11b-CD11c+macrophages, TNF-α and IL-10 in the respiratory tract of allgroups. However, the increment of phagocyte numbers as well as their MHC-IIexpression were higher in Pg05 mice than the other groups. In addition, Pg05mice showed a lower TNF-α/IL-10 ratio when compared to Pg06 and Pg534groups. In order to understand the mechanisms involved in the differentialimmune responses induced by the peptydoglicans obtained from different strainsof lactobacilli, we studied the interactions with mice lung epithelial cells(LEC) or alveolar macrophages (AM) using invitro systems. In this way, LECor AM were cultured 24 h in the absence orpresence of S. pneumoniaewith orwithout the addition of Pg05, Pg06 or Pg534. We demonstrated that 90% of LEC andAM remained viable after the treatments with Pgs. Pg05 (50 ug/mL) significantlymodulated the activation of AM by an increase of IL-1β and KC (p<0.05). Inthe same way, Pg05 was able to increase the production of KC by LEC (p<0.05).Inconclusion, the immunomodulatory effect of Pg05 is a strain specific propertyand it could act inducing the activation of epithelial cells and macrophages,leading to enhance the immune response against pathogens in immunocompromisedhosts. This particular feature of Pg05 opens interesting questions regardingthe molecular differences between probiotic and not probiotic peptidoglycans.