Recovery of B cells in malnourished mice by nasally administered Lactobacillus rhamnosus

VILLENA, JULIO; BARBIERI, NATALIA; HERRERA, MATÍAS; SALVA, SUSANA; KITASAWA, HARUKI; FUJIE, HORI; ALVAREZ, SUSANA

Génova

Congreso; 4th Congress of European Microbiologists FEMS 2011; 2011

The nasal administration of Lactobacillus rhamnosus CRL1505 (Lr05) is able to improve the adaptive immune response against Streptococcus pneumoniae in malnourished mice. In this work, we studied the effect of Lr05 treatment on the recovery of bone marrow (BM), spleen and lung B cells, during the repletion of malnourished mice. Weaned mice were malnourished with a protein-free diet (PFD) for 21d and then repleted with a balanced diet (BD) for 7d or BD 7d with Lr05 nasal administration (108cells/mouse/d) on d 6 and 7 (BD+Lr05). The malnourished control mice (MC) received PFD while the well-nourished control group (WC) consumed BD. Changes in BM, spleen and lung B cells were evaluated by flow cytometric analysis (CD19, B220, CD24, IgM, IgD). Malnutrition impaired the number of lymphocytes (FSC vs SSC) in all the studied organs. Both repletion treatments improved these parameters, however, BD+Lr05 was able to normalize the number of lymphocytes in BM and lung. MC mice showed a significant decrease of B cells (B220+CD19+) due to the diminution of the mature (B220highCD24lowIgM+IgD+) and immature (B220lowCD24highIgM+IgD-) B cells. BD+Lr05 treatment was more effective than BD to improve the number of BM and spleen immature B cells (WN=7.8±0.5; MN=0.4±0.2; BD=4.9±0.9; BD+Lr05=7.1±0.8 106cells/spleen) and lung mature B cells (WNC=1.4±0.2; MNC=0.4±0.02; BD=0.9±0.2; BD+Lr05=1.9±0.2 105cells/lung). In conclusion, the nasal administration of Lr05 during repletion of malnourished mice promotes the recovery of B cells in hematopoietic organs and in lung that would allow the improvement of the humoral immune response.