To understand the kinetics of phenotypic changes of lung macrophages, the surface expression of both CD11c and CD11b integrins on AM (as defined by forward and side-scatter gating) was assessed by FACS on bronchoalveolar lavage fluid (BALF) cells at time-points directly following infection of groups of 4 C57BL/6 mice with low dose (1×103) or high dose (1×106 ) C. burnetii. This evidence concerns the gene ITGAM and infection.