title: In vitro model of attachment of Giardia intestinalis trophozoites to IEC-6 cells, an intestinal cell line.
abstract: Attachment of giardias to intestinal cells has been difficult to study because of a lack of a convenient in vitro model. We developed an assay for attachment of radiolabeled trophozoites to IEC-6 cells that can be done in microtiter trays. Attachment was confirmed by scanning and transmission electron microscopy. Trophozoites remained attached to the IEC-6 cells for 24 h with little evidence of damage to the IEC-6 cells. Preincubation of trophozoites with cytochalasins A, B, and D reduced attachment to approximately 20% of that of controls, whereas colchicine had no effect. Chelation of divalent cations with EDTA and EGTA [ethylene glycol-bis(beta-aminoethyl ether)-N,N,N',N'-tetraacetic acid] reduced attachment to 24 and 26% of control values, respectively, and incubation at 4 degrees C reduced attachment to 7% of the value for controls incubated at 37 degrees C. Glutaraldehyde fixation of trophozoites or IEC-6 cells resulted in significantly diminished attachment to the live substrate (17 and 40% of control values, respectively). Coincubation of IEC-6 cells and trophozoites on a rotary shaker resulted in detachment of 40% of trophozoites, but EDTA, EGTA, glutaraldehyde fixation of trophozoites, and low temperature diminished attachment markedly and significantly. Similar results were obtained in selected experiments with three strains of giardia.
authors.affiliation: Medical Services, Veterans Administration Medical Center, Martinez, California 94553.
authors.forename: R E
authors.initials: RE
authors.lastname: McCabe
authors.forename: G S
authors.initials: GS
authors.lastname: Yu
authors.forename: C
authors.initials: C
authors.lastname: Conteas
authors.forename: P R
authors.initials: PR
authors.lastname: Morrill
authors.forename: B
authors.initials: B
authors.lastname: McMorrow
mesh_terms: D000818:Animals; D002460:Cell Line; D003078:Colchicine / Q000494:pharmacology; D003572:Cytochalasins / Q000494:pharmacology; D004492:Edetic Acid / Q000494:pharmacology; D004533:Egtazic Acid / Q000494:pharmacology; D005872:Giardia / Q000378:metabolism / Q000502:physiology*; D005976:Glutaral / Q000494:pharmacology; D006801:Humans; D007421:Intestine, Small / Q000166:cytology / Q000378:metabolism / Q000382:microbiology*; D008854:Microscopy, Electron; D013696:Temperature
chemical_list: D003572:Cytochalasins; D004533:Egtazic Acid; D004492:Edetic Acid; D003078:Colchicine; D005976:Glutaral