Figure 3. Immunofluorescence staining of paraffin-embedded thick sections of midgut tissue from the second instar Spodoptera frugiperda. Strong immunofluorescent signals were observed in panels A and D (anterior section), and B and E (posterior section) of the larval midgut, after incubation with Mab 7D6 (primary antibody), followed by goat anti-mouse IgG conjugated to Cy5 (secondary antibody). No immunofluorescent signals were observed in panels C and F, incubated with blocking agent and secondary antibody alone. Panels on the left are fluorescent images, while panels on the right are fluorescent images overlaid onto light microscopy images of the same sections. BM = Basement membrane, EP = epithelial cell, GC = goblet cell, H = hemolymph, L = lumen, M = Malpighian tubules. Scale bar = 20 μm.