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

HERRERA HM, SALVA S, VILLENA J, BARBIERI NP, ALVAREZ S

Congreso; XXV Jornadas Cientificas de la Asociación de Biología de Tucumán; 2008

Nasal administration of Lactobacillus casei CRL 431 (Lc) 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 not viable Lc (VLc; NVLc) on local and systemic innate immune response in a malnutrition experimental model. Malnourished mice were fed with a balanced conventional diet during 7d and were nasally treated on d6 and d7 with VLc or NVLc. At the end of each treatment (d8) mice were challenged intranasally with Sp. Leucocytes counts in bronchoalveolar fluid (BAL); phagocytic activity of alveolar macrophages (NBT+ cells); total and differential leucocytes counts in blood and bone marrow (BM) and mieloperoxidase activity in blood and BM (PX+) were determined. Before challenge, VLc and NVLc administration increased blood Px+ cells and leucocytes 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+ cells were significantly higher in VLc than in NVLc mice. These findings demonstrated that viability of lactic bacteria is important for the recovery of mielopoyesis.