Distribution of Cryptosporidium parvum sporozoite apical organelles during attachment to and internalization by cultured biliary epithelial cells.
Although accumulating evidence supports an active role for host cells during Cryptosporidium parvum invasion of epithelia, our knowledge of the underlying parasite-specific processes triggering such events is limited. In an effort to better understand the invasion strategy of C. parvum, we characterized the presence and distribution of the apical organelles (micronemes, dense granules, and rhoptry) through the stages of attachment to, and internalization by, human biliary epithelia, using serial-section electron microscopy. Novel findings include an apparent organized rearrangement of micronemes upon host cell attachment. The apically segregated micronemes were apposed to a central microtubule-like filamentous structure, and the more distal micronemes localized to the periphery and apical region of the parasite during internalization, coinciding with the formation of the anterior vacuole. The morphological observations presented here extend our understanding of parasite-specific processes that occur during attachment to, and internalization by, host epithelial cells.
O'Hara
Steven P
SP
The Center for Basic Research in Digestive Diseases, Division of Gastroenterology and Hepatology, Mayo Medical School, Clinic, and Foundation, Rochester, Minnesota 55905, USA.
Huang
Bing Q
BQ
Chen
Xian-Ming
XM
Nelson
Jeremy
J
LaRusso
Nicholas F
NF
D000818:Animals; D001652:Bile Ducts / Q000166:cytology / Q000469:parasitology*; D002461:Cell Line, Transformed; D016785:Cryptosporidium parvum / Q000502:physiology / Q000648:ultrastructure*; D003594:Cytoplasmic Granules / Q000469:parasitology / Q000648:ultrastructure; D004847:Epithelial Cells / Q000469:parasitology; D006790:Host-Parasite Interactions; D006801:Humans; D046529:Microscopy, Electron, Transmission / Q000379:methods; D008870:Microtubules / Q000469:parasitology / Q000648:ultrastructure; D015388:Organelles / Q000469:parasitology / Q000648:ultrastructure*; D014617:Vacuoles / Q000469:parasitology / Q000648:ultrastructure