Figure 9.

Interleukin-18 binding protein (IL-18BP) expression is localized to the splenic T cell-rich regions among cells expressing both Mac-3 and IL-18. (A) Representative IL-18BP immunohistochemistry results from splenic sections from wild-type and IL-18BPKO animals. Unlike the pattern of distribution seen for IL-18, IL-18BP was not prominent among the red pulp. Rather, IL-18BP-expressing cells were relatively abundant in the white pulp and appear to have a dendritic morphology. (B) Further examination of IL-18BP using immunofluorescence revealed that IL-18BP-expressing cells (green) reside in the T cell-rich zone of the spleen and are generally surrounded by CD3-expressing cells (red). (C) In addition, IL-18BP-expressing cells (green) were found to express Mac-3 (red), a marker expressed by macrophage as well as dendritic cells. (D) Finally, IL-18BP-expressing cells (green) also produce IL-18 (red). For (B–D), blue is DAPI and images were taken at 400× magnification. Data are representative of splenic sections from eight mice.