title: Paramagnetic microspheres as immunological markers for light and electron microscopy.
abstract: M-450 Dynabeads are magnetizable polystyrene microspheres 4.5 micron in diameter to which antibodies of IgM isotype can be physically adsorbed. Antibody-coated Dynabeads can be used to label cell surfaces and then to separate the rosetted cells by application of an external magnetic field. We demonstrate here, using cell lines K562 and U937 and the previously undescribed monoclonal antibodies CH-F42 and CH-E25, that Dynabeads can also be used to label cells at the ultrastructural level. Dynabeads can therefore provide a useful bridge between light and electron microscopy. The preservation of specific rosettes at the ultrastructural level without the formation of artifactual aggregates requires rapid but gentle fixation in dilute suspension. We have achieved this by fixing briefly in a large volume of buffered glutaraldehyde followed by neutralization of excess glutaraldehyde with ethanolamine.
authors.affiliation: Department of Haematological Medicine, University of Cambridge Clinical School, U.K.
authors.forename: M T
authors.initials: MT
authors.lastname: Rana
authors.forename: E C
authors.initials: EC
authors.lastname: Pearson
authors.forename: C R
authors.initials: CR
authors.lastname: Barker
mesh_terms: D000818:Animals; D000911:Antibodies, Monoclonal; D002460:Cell Line; D007075:Immunoglobulin M; D004915:Leukemia, Erythroblastic, Acute / Q000473:pathology; D008280:Magnetics; D008854:Microscopy, Electron / Q000379:methods; D008858:Microscopy, Phase-Contrast / Q000379:methods; D008863:Microspheres; D011137:Polystyrenes; D051381:Rats; D012397:Rosette Formation / Q000379:methods; D014407:Tumor Cells, Cultured / Q000648:ultrastructure
chemical_list: D000911:Antibodies, Monoclonal; D007075:Immunoglobulin M; D011137:Polystyrenes