Figure 5.

Effect of non-viable Lactobacillus rhamnosus CRL1505 (HK1505) and its peptidoglycan (PG1505) on the resistance to secondary pneumococcal pneumonia after the nasal administration of the viral pathogen-associated molecular pattern poly(I:C). Infant mice were nasally primed with HK1505 or PG1505 during two consecutive days, challenged with three once-daily doses of poly(I:C) and, infected with two different doses of Streptococcus pneumoniae 5 days after the last poly(I:C) administration (A). Non-treated infant mice stimulated with poly(I:C) and challenged with S. pneumoniae were used as controls. Lung bacterial cells counts (B), hemocultures (C), lactate dehydrogenase (LDH) activity and albumin concentrations in bronchoalveolar lavages (BAL) (D,E), and lung histopathological examination (D,E) were determined on day 2 post-pneumococcal challenge. Scale bar = 100 μm. The results represent data from three independent experiments. Significant differences between treated and control groups, *P < 0.05, **P < 0.01.