Figure 2

Delayed-type hypersensitivity skin test responses in healthy and footrot-affected sheep treated with selenium or saline. Footrot-affected (FR) sheep had an attenuated delayed-type hypersensitivity (DTH) response to keyhole limpet hemocyanin (KLH) compared with healthy sheep, as measured by A) ear thickness (overall: P = 0.006), B) ear wheal diameter (overall: P = 0.02), and C) body wheel diameter (overall: P = 0.04). Treatment of FR affected sheep with selenium (FR-Se) for 3 months improved the DTH response in FR-Se affected sheep, as measured by A) ear thickness (96 h after KLH challenge: P = 0.04 compared to FR-Saline sheep), and B) ear wheal diameter (72 h after KLH challenge: P = 0.09). After stratifying FR-affected sheep by whole-blood Se (WB-Se) status at the time of the immune assay (WB-Se cut-off: 250 ng/mL), sheep with WB-Se concentrations above 250 ng/mL (FR-High Se) had stronger DTH responses to KLH than sheep with WB-Se concentrations below 250 ng/mL (FR-Low Se), as measured by D) ear thickness (overall: P = 0.04), E) ear wheal diameter (72 h after KLH challenge: P = 0.10), but not by F) body wheel diameter (overall: P = 0.58).