FIG. 4.

Degranulation of NK cells. To show evidence of NK cell release of cytotoxic granule contents, cells were stained for CD107a following incubation with K562 cells or were left unstained not. (a) PBMC from noninfected (non-inf.) animals stained for CD107a; (b) PBMC from noninfected animals incubated with K562 cells and stained for CD107a; (c) PBMC from noninfected animals stimulated with IL-15 for 18 h and stained for CD107a; and (d) IL-15-stimulated PBMC from noninfected animals incubated with K562 and stained with CD107a. (e to k) PBMC from O1 Campos FMDV-infected pigs days 1 to 7 after infection, respectively. Histograms are from a single determination from two separate experiments.