that is epithelial cells exposed to leukocytes for short periods ( 5-60 minutes ) or to low dose levels ( 10 ( 5 ) - 10 ( 7 ) cells/ml ) shows leukocyte adhesion and penetration beneath the superficial layer of the epithelium , ( stage 1 and 2 ) , while longer exposures ( 2-3 hours ) or higher numbers of leukocytes ( 10 ( 7 ) - 10 ( 8 ) cells/ml ) , leads to deeper penetration of epithelium by leukocytes and epithelial injury ( stages 3,4 , and 5 ) .
C0014597
epithelial cells
C0014609
epithelium