Development of the vitellaria of the liver fluke, Fasciola hepatica in therat host

The development of the vitellaria of Fasciola hepatica within the liver of its rat host was studied by means of whole-mount stained preparations and t ransmission electron microscopy, together with light and electron immunocyt ochemistry using an antibody to vitelline protein B, an eggshell precursor protein synthesized by F. hepatica. No vitelline cells could be identified in flukes recovered from the liver parenchyma, by any of the methods used. In contrast, follicles were present in flukes at the earliest time of recov ery from the bile duct, namely, 5 weeks 3 days post-infection. The vitellar ia in these flukes formed a row of small follicles on either side of the bo dy. Development of the follicles was rapid: by 6 weeks 3 days, the vitellar ia resembled those in the adult fluke and eggs were present in the uterus. Immunolabelling was confined to the shell protein globules in the vitelline cells, confirming the packaging of the eggshell protein within the shell g lobule clusters.