Immunohistochemical localisation of CsGRN in infected Balb/c mouse livers. Sections of Balb/c mouse livers infected with C. sinensis treated with mouse anti-CsGRN serum (b, d, f, h, j and l) or mouse naïve serum (a, c, e, g, i and k). During early infection (1 month), CsGRN was observed mainly surrounding the bile ducts where parasites reside, and brown granules were found around cell nuclei, which explained how CsGRN entered the biliary epithelium cells across the cell membrane (d). From 2 months post-infection, CsGRN was also seen within the hepatocytes (f, h, j and l). With prolonged infection, more CsGRN gathered in bile duct epithelial cells and hepatocytes. Positive hepatocytes and biliary epithelium cells were even found in the smaller bile duct where adult worm could not reach. a, b normal, c, d 1 month, e, f 2 months, g, h 3 months, i, j 4 months and (k, l) 6 months post-infection. Arrows indicate positive cells. The images were magnified at 1,000× (scale-bar: 20 μm)