FIG 2.

Immunohistology for sHDAg in NGS- and RT-PCR-positive (animals 1 and 3 [A to F]) and negative (animal 7 [G]) animals, and a table of animals included in the study. (A) Brain. Viral antigen is expressed in the nucleus, cytoplasm, and cell processes of numerous neurons. (B) Liver. Individual hepatocytes (large arrows) are strongly positive, and macrophages (arrowheads) and endothelial cells (small arrows) are found to also express viral antigen. (C) Liver. A closer view shows that a substantial proportion of hepatocytes exhibit both cytoplasmic and nuclear (arrowheads) sHDAg expression. On the right, there is also one individual hepatocyte with an exclusively nuclear reaction (arrow). (D) Kidney. In a group of tubules (T), the majority of epithelial cells exhibit variably intense viral antigen expression. Occasional leukocytes in the interstitium (arrowhead) are also positive. (E) Lung. There are several individual positive epithelial cells (arrows); some subepithelial leukocytes are also found to express viral antigen (arrowhead). (F) Spleen. There is extensive viral antigen expression. Positive cells often have the morphology of macrophages (arrowheads). (G) RT-PCR-negative animal (animal 7), liver immunohistology for sHDAg. There is no evidence of sHDAg expression. Horseradish peroxidase method, hematoxylin counterstain. Note that the finely granular brownish staining in some Kupffer cells and hepatocytes in panels C and G is due to bile pigment and/or hemosiderin. (H) Table of animals included in the study.