Luminal immune cell invasion scoring. The presented quarter lobules were used to characterize the degree of luminal immune cell invasion observed in saline and Staph. aureus quarter lobules; scores 1–3 are presented. A Depicts a score of 1 which signifies no luminal infiltration; B depicts a score of 2 with infiltration in fewer than half the lobule lumens (arrows); and C denotes a score of 3 which is marked infiltration in most lumens. Scale bars = 200 µm.