<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