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PubMed1981

Morphological and adhesive changes to cultured chick kidney cells following parasitization with Eimeria tenella (Protozoa: Coccidia).

Cultured adult chick kidney (CK) cells inoculated with sporozoites of Eimeria tenella showed progressive alterations in their morphological and adhesive characteristics. Scanning electron microscopy (SEM) showed that during a 3-day period following the inoculation of parasites there was a gradual loss of contact between the cells. Initially, the cells remained connected by long cytoplasmic bridges but with the breakdown of these, the cells began to round up, losing complete contact with each other and remaining attached to the substratum by means of retraction fibres. By 3 days many cells had completely detached. The factors inducing these alterations were transmissable via the medium as the alterations were mimicked by non-parasitized cells in co-culture with parasitized cells. Studies with the reflection interference microscope (RIM) showed that the changes were accompanied by an increase in the cell-substrate separation distance and the loss of focal contacts. These changes were not effected by substances transmissable via the medium. Parasitized cells showed enhanced agglutination with Concanavalin A (Con A) which could be eliminated by pre-fixation. The possibility that changes to the host cell indicate a rearrangement of cytoskeletal apparatus is discussed.

Agglutination↗
PubMed1991

Characterization and immunolocalization of an oocyst wall antigen of Cryptosporidium parvum (Protozoa: Apicomplexa).

A monoclonal antibody (OW-IGO) raised against purified excysted oocysts of Cryptosporidium parvum reacted in an immunofluorescence assay with the oocyst wall. The corresponding antigen was localized by immunoelectron microscopy in fibrillous material present in the parasitophorous vacuole of developing macrogametes and in the wall of both single and double layered sporulating oocysts. Gold particles were also detected over electron-lucent vesicles of the macrogametes by immunoelectron microscopy. On Western blotting of C. parvum oocyst extracts, major bands at 250 and 40 kDa and several minor components were recognized by Mab OW-IGO. Almost complete abolition of Western blot reactivity occurred after periodate oxidation of oocyst antigen, suggesting that monoclonal antibody OW-IGO reacts with a carbohydrate epitope. Taken together, our results suggest that a fibrillous glycoproteinic material is released in the parasitophorous vacuole from electron-lucent vesicles during gametogenesis, and later condensed in the oocyst wall.

Animals↗