Fig. 1
Experimental mouse model with three repeated NTHi infections (series 2): 3-week-old male mice were fed during 5 weeks with a vitamin D deficient or sufficient diet and were maintained under respective diets during the whole study period. At the age of 8 weeks, mice were acclimatized for 1 week to cigarette smoke or ambient air in soft restrains and then exposed to cigarette smoke (6 cigarettes/day 5 day/week) or room air during the study period. In series 2, at week 6 of exposure, mice were infected oropharyngeally with 106 CFU/ml NTHi and maintained one week in quarantine with no exposure and then CS or air exposure were resumed. They were infected again on week 10 and 14 of exposure and measurements were performed 72 h after the last infection