Effect of lactobacilli peptidoglycans on the respiratory innate immune response to <i>Streptococcus pneumoniae</i> infection in malnourished mice.

<p>Immunocompromised-malnourished mice were replete for 7 days with a balanced conventional diet (BCD) or BCD supplemented with peptidoglycans from <i>Lactobacillus rhamnosus</i> CRL1505 (BCD+PG05), <i>L</i>. <i>plantarum</i> CRL1506 (BCD+PG06) or <i>L</i>. <i>rhamnosus</i> CRL534 (BCD+PG534), and then challenged with <i>S</i>. <i>pneumoniae</i>. The respiratory innate immune response was studied two days after the pneumococcal challenge. (A) Number of broncho-alveolar lavages (BAL) leukocytes. (B) Number of BAL macrophages. (C) Number of BAL neutrophils. (D) Number of lung macrophages (CD11c⁺F480⁺MHCII⁺). (E) Number of lung neutrophils (CD₄₅⁺Gr1⁺). Results represent data from three independent experiments. Results are expressed as mean ± SD. Asterisks represent statistical differences compared with BCD+PG05 group. * p < 0.05, ** p ≤ 0.001, ***/**** p ≤ 0.001.</p

Effect of lactobacilli peptidoglycans on lung, spleen and thymus T cells numbers after <i>Streptococcus pneumoniae</i> infection in malnourished mice.

<p>Immunocompromised-malnourished mice were replete for 7 days with a balanced conventional diet (BCD) or BCD supplemented with peptidoglycans from <i>Lactobacillus rhamnosus</i> CRL1505 (BCD+PG05), <i>L</i>. <i>plantarum</i> CRL1506 (BCD+PG06) or <i>L</i>. <i>rhamnosus</i> CRL534 (BCD+PG534), and then challenged with <i>S</i>. <i>pneumoniae</i>. The numbers of T cells were studied ten days after the pneumococcal challenge. (A) Number of total lymphocytes in lung. (B) Number of CD3⁺CD4⁺ and CD3⁺CD8⁺ T cells in lung. (C) Number of total lymphocytes in spleen. (D) Number of CD3⁺CD4⁺ and CD3⁺CD8⁺ T cells in spleen. (E) Number of total lymphocytes in thymus. (F) CD4^-CD8^-CD25⁺ and CD4⁺CD8⁺CD3^low (immature cells). (G) CD3⁺CD4⁺ and CD3⁺CD8⁺ (mature cells). Results are expressed as mean ± SD. Asterisks represent statistical differences compared with BCD+PG05 group. * p < 0.05, **p < 0.005, ***/**** p ≤ 0.001.</p

Effect of lactobacilli peptidoglycans on the systemic innate immune response to <i>Streptococcus pneumoniae</i> infection in malnourished mice.

<p>Immunocompromised-malnourished mice were replete for 7 days with a balanced conventional diet (BCD) or BCD supplemented with peptidoglycans from <i>Lactobacillus rhamnosus</i> CRL1505 (BCD+PG05), <i>L</i>. <i>plantarum</i> CRL1506 (BCD+PG06) or <i>L</i>. <i>rhamnosus</i> CRL534 (BCD+PG534), and then challenged with <i>S</i>. <i>pneumoniae</i>. The systemic innate immune response was studied two days after the pneumococcal challenge. (A) Number of blood leukocytes. (B) Number of blood neutrophils. (C) Score of blood peroxidase. (D) Number of spleen macrophages (CD11c⁺F480⁺MHCII⁺). Results represent data from three independent experiments. Results are expressed as mean ± SD. Asterisks represent statistical differences compared with BCD+PG05 group. * p < 0.05, ** p < 0.005, ***/**** p ≤ 0.001.</p

Resistance to pneumococcal infection.

<p>Resistance to pneumococcal infection.</p

Effect of lactobacilli peptidoglycans on TNF-α and IL-10 production after <i>Streptococcus pneumoniae</i> infection in malnourished mice.

<p>Immunocompromised-malnourished mice were replete for 7 days with a balanced conventional diet (BCD) or BCD supplemented with peptidoglycans from <i>Lactobacillus rhamnosus</i> CRL1505 (BCD+PG05), <i>L</i>. <i>plantarum</i> CRL1506 (BCD+PG06) or <i>L</i>. <i>rhamnosus</i> CRL534 (BCD+PG534), and then challenged with <i>S</i>. <i>pneumoniae</i>. The levels of cytokines were studied two days after the pneumococcal challenge. (A) TNF-α, (B) IL-10, and (C) TNF-α/IL-10 ratio in broncho-alveolar lavages (BAL). (D) TNF-α, (E) IL-10, and (F) TNF-α/IL-10 ratio in serum. Results are expressed as mean ± SD. Asterisks represent statistical differences compared with BCD+PG05 group. * p < 0.05, ** p < 0.005, ***/**** p ≤ 0.001.</p

Effect of lactobacilli peptidoglycans on lung, spleen and bone marrow (BM) B cells numbers after <i>Streptococcus pneumoniae</i> infection in malnourished mice.

<p>Immunocompromised-malnourished mice were replete for 7 days with a balanced conventional diet (BCD) or BCD supplemented with peptidoglycans from <i>Lactobacillus rhamnosus</i> CRL1505 (BCD+PG05), <i>L</i>. <i>plantarum</i> CRL1506 (BCD+PG06) or <i>L</i>. <i>rhamnosus</i> CRL534 (BCD+PG534), and then challenged with <i>S</i>. <i>pneumoniae</i>. The numbers of B cells were studied fifteen days after the pneumococcal challenge. Different lung B cells subpopulations: (A) B220^lowCD19⁺CD24^high (immature cells) and B220^highCD19⁺CD24^low (mature cells) (B) IgD⁺IgM^-CD24^low (mature cells) Different spleen B cells subpopulations: (C) B220^lowCD19⁺CD24^high (immature cells) and B220^highCD19⁺CD24^low (mature cells). (D) IgD⁺IgM⁺CD24^low (immature cells) and IgD⁺IgM^-CD24^low (mature cells). Different B cells subpopulations in BM: (E) B220^lowIgM^-CD24^high pre-pro B cells and B220^highIgM⁺CD24^low mature B cells. (F) IgD^-IgM⁺CD24^high immature B cells and IgD⁺IgM⁺CD24^low mature B cells. Results represent data from three independent experiments. Results are expressed as mean ± SD. Asterisks represent statistical differences compared with BCD+PG05 group. * p < 0.05, ** p < 0.005, ***/**** p ≤ 0.001.</p

Effect of lactobacilli peptidoglycans on lung injuries induced by the infection of <i>Streptococcus pneumoniae</i> in malnourished mice.

<p>Immunocompromised-malnourished mice were replete for 7 days with a balanced conventional diet (BCD) or BCD supplemented with peptidoglycans from <i>Lactobacillus rhamnosus</i> CRL1505 (BCD+PG05), <i>L</i>. <i>plantarum</i> CRL1506 (BCD+PG06) or <i>L</i>. <i>rhamnosus</i> CRL534 (BCD+PG534), and then challenged with <i>S</i>. <i>pneumoniae</i>. Two days after pneumococcal challenge, lung damage was evaluated by histological studies and biochemical parameters. (A) Lungs histological examination. Hematoxylin and eosin stained light micrographs, original magnification ×100. Recruited inflammatory cells (RIC), reduction of alveolar airspaces (RAA), moderate inflammatory response (MIR), conserved alveolar air spaces (CAA). (B) Lactate dehydrogenase (LDH) activity and, albumin concentration in broncho-alveolar lavages (BAL). The results represent data from three independent experiments. Results are expressed as mean ± SD. Asterisks represent statistical differences compared with the BCD+PG05 group. * p < 0.005, ** p ≤ 0.001.</p

Effect of lactobacilli peptidoglycans on anti-pneumococcal antibodies levels after <i>Streptococcus pneumoniae</i> infection in malnourished mice.

<p>Immunocompromised-malnourished mice were replete for 7 days with a balanced conventional diet (BCD) or BCD supplemented with peptidoglycans from <i>Lactobacillus rhamnosus</i> CRL1505 (BCD+PG05), <i>L</i>. <i>plantarum</i> CRL1506 (BCD+PG06) or <i>L</i>. <i>rhamnosus</i> CRL534 (BCD+PG534), and then challenged with <i>S</i>. <i>pneumoniae</i>. The levels of antibodies were studied fifteen days after the pneumococcal challenge. (A) Levels of anti-peumococcal IgA, (B) IgG and (C) IgM in broncho-alveolar lavages. (D) Levels of anti-peumococcal IgA, (E) IgG and (F) IgM in serum. Results represent data from three independent experiments. Results are expressed as mean ± SD. Asterisks represent statistical differences compared with BCD+PG05 group. * p < 0.05, **p < 0.005, ***/**** p ≤ 0.001.</p

Effect of lactobacilli peptidoglycans on the opsonophagocytic activity of anti-pneumococcal antibodies after <i>Streptococcus pneumoniae</i> infection in malnourished mice.

<p>Immunocompromised-malnourished mice were replete for 7 days with a balanced conventional diet (BCD) or BCD supplemented with peptidoglycans from <i>Lactobacillus rhamnosus</i> CRL1505 (BCD+PG05), <i>L</i>. <i>plantarum</i> CRL1506 (BCD+PG06) or <i>L</i>. <i>rhamnosus</i> CRL534 (BCD+PG534), and then challenged with <i>S</i>. <i>pneumoniae</i>. The opsonophagocytic activity of antibodies were studied fifteen days after the pneumococcal challenge. Results represent data from three independent experiments. Results are expressed as mean ± SD. Asterisks represent statistical differences compared with BCD+PG05 group. * p < 0.05, ** p < 0.005, *** p ≤ 0.001.</p

Dietary Supplementation with Lactobacilli Improves Emergency Granulopoiesis in Protein-Malnourished Mice and Enhances Respiratory Innate Immune Response

<div><p>This work studied the effect of protein malnutrition on the hemato-immune response to the respiratory challenge with <i>Streptococcus pneumoniae</i> 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 <i>Lactobacillus rhamnosus</i> 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 <i>L. rhamnosus</i> 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.</p></div