Nasally Administered Lactobacillus rhamnosus Accelerate the Recovery of Humoral Immunity in B Lymphocyte-Deficient Malnourished Mice.
ABSTRACT The ability of nasally administered Lactobacillus rhamnosus CRL1505 to accelerate the recovery of respiratory B cell-mediated immunity against pneumococcal infection in replete malnourished mice was evaluated. Weaned mice were malnourished after consumption of a protein-free diet for 21 d. Malnourished mice were fed a balanced conventional diet (BCD) for 7 d (BCD group) or a BCD for 7 d with supplemental L. rhamnosus CRL1505 by the nasal route during the last 2 d (BCD+Lr group). Nonreplete malnourished and normal mice were used as the malnourished (MNC) and the well-nourished (WNC) control groups, respectively. Mice were challenged with Streptococcus pneumoniae at the end of each dietary treatment. The immune response was studied before the challenge and at different times postinfection. The MNC mice had less resistance to pneumococcal infection, fewer mature and immature B cells in lung and spleen, and a reduced production of specific antibodies compared with WNC mice. The BCD treatment did not induce a complete normalization of the number B cell populations and antibody amounts. However, the BCD+Lr group had normal numbers of spleen and lung B cells. Moreover, the BCD+Lr mice had a significantly lower susceptibility to S. pneumoniae infection and higher amounts of anti-pneumococcal antibodies. Although further studies are necessary to clarify the effect of malnutrition and nasally administered lactobacilli in other immune cell populations involved in the protection against respiratory pathogens, this work gives evidence of the importance of using nasal priming with probiotics to accelerate the recovery of respiratory immunity in immunocompromised malnourished hosts.
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ABSTRACT: This work studied the effect of protein malnutrition on the hemato-immune response to the respiratory challenge with Streptococcus pneumoniae and evaluated whether the dietary recovery with a probiotic strain has a beneficial effect in that response. Three important conclusions can be inferred from the results presented in this work: a) protein-malnutrition significantly impairs the emergency myelopoiesis induced by the generation of the innate immune response against pneumococcal infection; b) repletion of malnourished mice with treatments including nasally or orally administered Lactobacillus rhamnosus CRL1505 are able to significantly accelerate the recovery of granulopoiesis and improve innate immunity and; c) the immunological mechanisms involved in the protective effect of immunobiotics vary according to the route of administration. The study demonstrated that dietary recovery of malnourished mice with oral or nasal administration of L. rhamnosus CRL1505 improves emergency granulopoiesis and that CXCR4/CXCR12 signaling would be involved in this effect. Then, the results summarized here are a starting point for future research and open up broad prospects for future applications of probiotics in the recovery of immunocompromised malnourished hosts.PLoS ONE 04/2014; 9(4):e90227. · 3.53 Impact Factor
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ABSTRACT: Previously we showed that orally administered Lactobacillus rhamnosus CRL1505 beneficially regulated the balance between pro- and anti-inflammatory mediators in the lungs of poly(I:C)-challenged mice, allowing an effective inflammatory response against the TLR3/RIG-I agonist but at the same time reducing tissue damage. The aim of the present study was to investigate whether oral administration of the CRL1505 strain was able to improve resistance against respiratory syncytial virus (RSV) infection in infant mice and to evaluate the immunological mechanisms involved in the immunobiotic effect. We demonstrated that treatment of 3-week old BALB/c mice with L. rhamnosus CRL1505 significantly reduce lung viral loads and tissue injuries after the challenge with RSV. Moreover, we showed that the protective effect achieved by the CRL1505 strain is related to its capacity to differentially modulate respiratory antiviral immune response. Our results shows that IFN-γ and IL-10 secreted in response to L. rhamnosus CRL1505 oral stimulation would modulate the pulmonary innate immune microenvironment conducting to the activation of CD103(+) and CD11b(high) dendritic cells and the generation of CD3(+)CD4(+)IFN-γ(+) Th1 cells with the consequent attenuation of the strong and damaging Th2 reactions associated with RSV challenge. Our results indicate that modulation of the common mucosal immune system by immunobiotics could favor protective immunity against respiratory viral pathogens with a high attack rate in early infancy, such as RSV.International immunopharmacology 07/2013; · 2.21 Impact Factor