Importance of lactic bacteria viability on innate immunity stimulation in malnourished mice

HERRERA MATÍAS; SALVA SUSANA; VILLENA JULIO; BARBIERI NATALIA; ALVAREZ SUSANA

Tafí del Valle. Tucumán

Jornada; XXV Jornadas Científicas de la Asociación de Biología de Tucumán; 2008

Asociación de Biología de Tucumán

Nasal administration of Lactobacillus casei CRL431 increases resistance to Streptococcus pneumoniae (Sp) infection in malnourished mice. The aim of this study was to investigate the effect of nasal administration of viable and non viable Lc (VLc; NVLc) on the local and systemic innate immune response in a malnutrition experimental model. Malnourished mice were fed a balanced conventional diet for 7d and nasally treated on d6 and d7 with VLc or NVLc. At the end of each treatment (d8) mice were challenged intranasally with Sp. Leukocytes counts in bronchoalveolar fluid (BAL); phagocytic activity of alveolar macrophages (NBT+ cells); total and differential leukocytes counts in blood and bone marrow (BM) and myeloperoxidase activity in blood and in bone marrow (Px) were determined. Before challenge, VLc and NVLc administration increased blood Px cells and leukocytes number, but only VLc treatment improved the number of mitotic, post mitotic and Px+ cells in BM. Both treatments increased number and activity of BAL and blood phagocytes after the challenge with Sp. In addition, both treatments improved Px activity in BM; however, Px+ were significantly higher in VLc than NVLc mice. These findings demonstrated that the viability of lactic bacteria is important for the recovery of myelopoiesis.