Lactobacillus rhamnosus CRL1505 improves emergency myelopoiesis against respiratory infection in immunocompromised host by cyclophosphamide

GRAMAJO-LÓPEZ, ANDRÉS; KOLLING, YANINA; ALVAREZ, SUSANA; SALVA, SUSANA

Buenos Aires

Congreso; Reunión Conjunta de Sociedades de Biociencias; 2017

Emergency myelopoiesis is critical to control the infection with pathogens. Patients undergoing chemotherapy have a damage in hematopoiesis associated with an ineffective immune response against infections. Lactobacillus rhamnosus CRL1505 diet supplementation has proved to be an interesting alternative to improves steady-state and emergency myelopoiesis. Although the viability of lactic acid bacteria is an important factor, it is possible to stimulate immunity by using the non-viable microorganism. In this work we evaluated whether L. rhamnosus CRL1505 was able to improve emergency myelopoiesis induced by Streptococcus pneumoniae (Sp) infection. Adult Swiss-mice were orally treated with viable or non-viable L. rhamnosus CRL1505 (Lr05V or Lr05NV, respectively) during five consecutive days. On day 6, lactobacilli-treated and untreated control mice received one intraperitoneal dose of cyclophosphamide (Cy 150 mg/kg). On day 3 post-Cy injection, mice were nasally challenged with Sp (107 UFC/mice). Innate and myelopoietic responses were evaluated after the pneumococcal challenge. The Cy group showed a high susceptibility to pneumococcal infection, an impaired innate immune response and a decrease of hematopoietic stem cells (HSCs) (Lin-Sca-1+c-Kit+) and myeloid multipotent precursors (MMPs) (Gr-1+Ly6G+Ly6C-) in bone marrow (BM). However, lactobacilli treatments were able to significantly increase blood neutrophils and peroxidase (Px)+ cells, and improve cytokine production and phagocytic capacity of alveolar macrophages. This, in turn, led to an early Sp lung clearance compared with the Cy group (p