Corneas were dissected from mouse eyes at 4 days post infection (dpi) and cut into small (1–2 mm diameter) fragments for subsequent digestion with 1 mg/ml collagenase type I and 0.5 mg/ml DNase (Sigma Chemical, St. Louis, MO)18 (link). Single cell suspensions were washed twice (300 × g, 5 min/wash) in PBS and then incubated on ice for 15 min with 2 µl anti-mouse Fc block (BD Pharmingen, San Diego, CA) in a total volume of 100 µl PBS-1% BSA. Following incubation, cells were centrifuged (300 × g, 5 min) and resuspended in 5% normal rat serum (Jackson Immuno Research, West Grove, PA) for an additional 15 min on ice. Cells were then labeled with 4 µl anti-mouse FITC-conjugated anti-CD45 (clone 30-F11, BD Pharmingen), and incubated in the dark on ice for 30 min. Following incubation, the cells were washed 3 times with PBS-1% BSA (300 × g, 5 min/wash) and resuspended in PBS-1% BSA and flow cytometry performed using a Cytomics FC500 (Beckman Coulter, Brea, CA) for CD45+ events, representing the numbers of fluorescent events identified in infected and control corneas and roughly corresponding to the number of leukocytes per cornea.