To accomplish MmuPV L1-K14 double fluorescent staining we made use of tyramide-based signal amplification (TSA) technique. This technique allows for easy multiplexing of immunofluorescent staining but perhaps its biggest advantage is that it permits double immunofluorescent staining using two unconjugated primary antisera raised in the same species. We have adopted a home-based method of TSA staining using reagents as described previously for performing L1-K14 dual fluorescent staining. \u00a0The general principle of TSA staining is described in Fig. 1. The first step involves staining of viral capsid using rabbit sera raised against L1 followed by HRP conjugated secondary antibody. The HRP-conjugated 2o antibody is then biotinylated using biotin conjugated with tyramide. We can then proceed to stain with antibody against cytokeratin-14 (raised in same species as L1 antibody, i.e. rabbit). Both antibodies can now be detected easily \u2013 i.e. L1 can be detected with anti-Streptavidin and K14 can be detected with an anti-rabbit 2o antibody. Several commercial kits also exist for performing TSA-based staining (e.g. PerkinElmer, Pierce and Thermo Scientific) and are being used readily in several laboratories.