Fig. 2
Intranasal pretreatment with EcN-Chim reduces airway inflammation. a Schematic representation of the pretreatment of recombinant E. coli Nissle expressing birch-grass pollen chimera (EcN-Chim) in a mouse model of poly-sensitization: Female BALB/c mice (n = 5) were pretreated with (EcN-Chim) and control E. coli Nissle (EcN-Ctrl) either orally (each 109 CFU in 300 µl gavage buffer) or intranasally (each 107 CFU in 30 µl in PBS) every second day (days 0, 2, 4, 6, 8) followed by intraperitoneal sensitization (days 10, 24, and 39) of a mixture of 5 µg rBet v 1, 5 µg rPhl p 1, and 5 µg rPhl p 5 adsorbed to aluminium hydroxide and after 1 week an intranasal challenge with 30 µl of mixture of 5 µg rBet v 1, 5 µg rPhl p 1, and 5 µg rPhl p 5 for 3 consecutive days. Mice were sacrificed 72 h after the last airway challenge (day 51) and blood, bronchoalveolar lavage (BAL), spleens and lungs were collected for further analysis. b IL-5 and IL-13 cytokines in BAL. c Representative lung tissue sections of one mouse per group stained with Periodic Acid Schiff (PAS) (Red; ×10 magnification; scale bars 100 µm); arrows indicate cell infiltration. d Absolute numbers of eosinophils in BAL. e Representative cytospins of BAL of one mouse per group stained with haematoxylin and eosin (H&E; ×100 magnification). Allergic: Poly-sensitized control. Oral + EcN-Chim: Oral pretreatment with EcN-Chim prior to poly-sensitization. Oral + EcN-Ctrl: Oral pretreatment with EcN-Ctrl prior to poly-sensitization. Nasal + EcN-Chim: Intranasal pretreatment with EcN-Chim prior to poly-sensitizazion. Nasal + EcN-Ctrl: Intranasal pretreatment with EcN-Ctrl prior to poly-sensitization. Naïve: No treatment or poly-sensitization. b, d represent mean ± SEM from pooled data of two independent experiments (total n = 10 mice per group). Error bars show mean ± SEM. *P < 0.05, **P < 0.01, ***P < 0.001 by Mann−Whitney U- test
