Lactobacillus rhamnosus CRL1505 improves emergency myelopoiesis against s. pneumoniae infection in immunosuppressed host by cyclophosphamide

GRAMAJO LOPEZ ANDRÉS; KOLLING YANINA; ALVAREZ SUSANA; SALVA SUSANA

Buenos Aires

Congreso; Reunión Conjunta de Sociedades de Biociencias; 2017

Sociedades de Biociencias

Emergency myelopoiesis is critical to control the infection withpathogens. Patients undergoing chemotherapy have a damagein hematopoiesis associated with an ineffective immune responseagainst infections. Lactobacillus rhamnosus CRL1505 diet supplementationhas proved to be an interesting alternative to improvessteady-state and emergency myelopoiesis. Although the viability oflactic acid bacteria is an important factor, it is possible to stimulateimmunity by using the non-viable microorganism. In this work weevaluated whether L. rhamnosus CRL1505 was able to improveemergency myelopoiesis induced by Streptococcus pneumoniae(Sp) infection. Adult Swiss-mice were orally treated with viable ornon-viable L. rhamnosus CRL1505 (Lr05V or Lr05NV, respectively)during five consecutive days. On day 6, lactobacilli-treated and untreatedcontrol mice received one intraperitoneal dose of cyclophosphamide(Cy 150 mg/kg). On day 3 post-Cy injection, mice werenasally challenged with Sp (107 UFC/mice). Innate and myelopoieticresponses were evaluated after the pneumococcal challenge. TheCy group showed a high susceptibility to pneumococcal infection,an impaired innate immune response and a decrease of hematopoieticstem cells (HSCs) (Lin-Sca-1+c-Kit+) and myeloid multipotentprecursors (MMPs) (Gr-1+Ly6G+Ly6C-) in bone marrow (BM). However,lactobacilli treatments were able to significantly increase bloodneutrophils and peroxidase (Px)+ cells, and improve cytokine productionand phagocytic capacity of alveolar macrophages. This, inturn, led to an early Sp lung clearance compared with the Cy group(p