Use of antisera directed against dsRNA to detect viral infections in formalin-fixed paraffin-embedded tissue

BackgroundThe detection of viral infection in paraffin-embedded, formalin-fixed tissue is notoriously difficult and often requires inherent knowledge about the specific virus being sought. For this reason, there is an ongoing need for reagents and methods which can identify a range of different virus types in paraffin embedded tissue.ObjectivesThe aim of this study was to optimise and validate the use of antisera directed against dsRNA (>50 bp in length) in paraffin-embedded formalin-fixed tissue samples.Study designdsRNA antisera were optimised for use in a range of virally-infected tissue culture cells, Coxsackie-infected mice and human tissues. The specificity of labelling was confirmed by pre-adsorption of antisera with poly-IC and by digestion of dsRNA with RNaseIII.ResultsTwo different polyclonal dsRNA antisera (J2 and K1) were capable of recognising dsRNA encoded by all the multiple different viral types (including (+) ssRNA viruses, dsRNA viruses and DNA viruses) tested in paraffin-embedded formalin fixed infected cells and tissues. In contrast, the enteroviral vp1 antisera detected only a subset of the (+) ssRNA viruses tested. Staining was not seen in uninfected cells or in uninfected control tissues. Positive staining was ablated following incubation of antisera with poly-IC or by pre-treating sections with RNaseIII prior to staining.ConclusionsThe dsRNA antisera J2 and K1 are useful for the detection of viral infection in formalin-fixed, paraffin-embedded, human tissue samples.