Immunohistochemical identification of infectious pancreatic necrosis virus in paraffin-embedded tissues of Atlantic salmon (Salmo salar).

Infectious pancreatic necrosis virus serotype Sp was identified by immunohistochemistry in formaldehyde-fixed and paraffin-embedded tissue of Atlantic salmon (Salmo salar). The immunoreaction was present in degenerating and necrotic cells in exocrine pancreatic cells. Cross reactions were observed with rabbit antisera against serotypes Sp, Ab, and VR-299 in neutralization tests and western blotting. Immunohistochemically, only Sp antiserum produced positive immunostaining to Sp antigens, whereas antisera to serotypes Ab and VR-299 were negative.