Hepatic tissue culture model for study of host-parasite interactions in alveolar echinococcosis

Abstract

An in vitro model for growth and differentiation of the metacestode tissue of the tapeworm Echinococcus multilocularis is described. This model simulates the organotropism of the parasite toward the liver of the intermediate host. In the presence of collagen-embedded primary hepatocytes from rats and humans, which can be kept in culture for 2 to 3 months, the parasitic vesicles grew by exogenous budding and multiplied about 12-fold within 3 weeks. In contrast, without the hepatocytes, the metacestodes rapidly degenerated. Development of protoscolices was seen only in the presence of rat hepatocytes but not in coculture of the metacestodes with hepatocytes of human origin, thus reflecting the in vivo situation during infection of rodents and in alveolar echinococcosis in humans. The experiments indicated that growth of the metacestodes and development of protoscolices depended on soluble low-molecular-weight factors released by the hepatocytes. The in vitro-grown metacestodes did not differ morphologically from the larvae found in infected intermediate hosts, and their infectivity was completely maintained. This report describes the first in vitro model of alveolar echinococcosis and will be the basis for future studies on host-parasite interactions of this important zoonosis.

In vitro culture of Mesocestoides corti metacestodes and isolation of immunomodulatory excretory–secretory products

“…Our observation of a preferential localization of M. corti larvae to the murine host liver, similar to previous observations made for metacestodes of the related cestode, E. multilocularis , suggested an advantageous role for liver factors or hepatocytes in fostering the establishment and development of M. corti larvae. To address this hypothesis, M. corti tetrathyridia freshly flushed from mice peritonea were seeded at an equal density (100 larvae/mL of culture medium) either in complete culture medium (DMEM10) or in complete medium supplemented with rat hepatoma cells (10 6 cells/mL of culture).…”

“…Like other tissue‐dwelling metacestodes, M. corti tetrathyridia preferentially lodged within the liver that might be due to the immune‐privileged status of the liver . However, our study, consistently with previous works on parasitic metacestodes , revealed a pro‐proliferative effect of liver cells on M. corti tetrathyridia. This suggests that the immune‐privileged status of the liver might not be the only advantage for cestodes but that hepatocytes may even provide factors promoting parasite proliferation.…”

Subcutaneous Taenia Crassiceps Infection in a Patient With Non-Hodgkin’s Lymphoma

“…When we used a co-culture system originally developed for the metacestodes of E. multilocularis, 4 T. crassiceps larvae could be kept in vitro. During a four-month observation period, the markedly vivid and motile larvae grew to a size of approximately 1-1.5 cm, including posterior buds.…”

myo-Inositol hexakisphosphate is a major component of an extracellular structure in the parasitic cestode Echinococcus granulosus

“…Cysts from E. multilocularis were generously given by Dr Klaus Brehm (Institut fu$ r Hygiene und Mikrobiologie der Universita$ t Wu$ rzburg, Germany). E. multilocularis larvae, obtained from infected patients and maintained in Mongolian jirds (Meriones unguiculatus), were cultivated in itro for 6 weeks as described previously [20]. The cysts were washed with PBS and a soluble extract from the cyst walls was obtained as described above for the ' mother ' bovine HCW.…”