Fig 7. Spn neuraminidases stimulate mucus containing secretions in a neuraminidases-dependent manner.

(A) URT tissue sections of mock- or Spn-infected infant mice were examined at day 5 post-infection. Sialic acid containing secretions were visualized through a SNL lectin staining that detects α-2,6 linked sialic acid (upper row), where green staining indicates sialic acid containing material and orange staining indicates Spn; or alcian blue-PAS staining for mucopolysaccharides (lower row). (B-C) To quantify sialic acid and mucus containing secretions in the URT of mice, retro-tracheal lavages were obtained from infant mice at day 5 p.i.. Immunoblots were performed with the lavages to determine the amount of α-2,3 linked sialic acid (B) or muc5ac mucin (C). Experiments were performed in duplicates and mean values of three independent experiments are shown with error bars corresponding to S.D., *,p<0.05 **,p<0.01, ***,p<0.001 by 1-way ANOVA followed by Dunnett’s multiple comparison test.