Intralobular stromal immune cell invasion scoring. The presented quarter lobules were used to characterize the degree of intralobular stromal immune cell invasion observed in saline and Staph. aureus quarter lobules; scores 1–4. A Depicts a score of 1 with no infiltration; B depicts a score of 2 where small isolated pockets of infiltration (arrows) are present; C exemplifies a score of 3 where cellular infiltration affects approximately 1/3 of the lobule; and D depicts a score of 4, marked infiltration affecting more than 2/3 of the lobule. Scale bars = 200 µm.