title: VVA-labelled cells in monkey visual cortex are double-labelled by a polyclonal antibody to a cell surface epitope.
abstract: The staining patterns produced by the lectin Vicia villosa and by a commercially available polyclonal antibody generated to substance P were analysed and compared in monkey visual cortex at the light and electron microscopic levels. Vicia villosa lectin labels the cell surface of a subpopulation of cortical cells, producing a meshlike pattern over the soma and proximal dendrites. The polyclonal antibody labels three distinct elements in the cortex: a pericellular epitope present on a subpopulation of non-pyramidal cells, and putative intracellular sites in a type of small pyramidal cell located at the layer 5/6 border, and in a small number of non-pyramidal cells in the underlying white matter. Because of the similarity of the appearance of the Vicia villosa lectin labelling and the pericellular labelling produced by the polyclonal antibody, further experiments were conducted to determine the relationship between the cell surface sites recognized by these markers. Double-labelling experiments show that both sites are present on the same population of cells, and at the ultrastructural level both markers appear to outline the intersynaptic cell membrane, sometimes extending around presynaptic elements. However, preadsorption experiments indicate that the markers recognize different sites on the cell membrane. Preadsorption experiments also show that the pericellular epitope recognized by the polyclonal antibody is unlikely to be substance P, but it may be structurally similar to keyhole limpet haemocyanin. Comparison of cortical and subcortical staining patterns produced with the polyclonal antibody and with a commonly used monoclonal antibody to substance P reveal that one of the putative intracellular epitopes recognized by the polyclonal antibody is likely to be substance P.
authors.affiliation: Department of Biological Structure, University of Washington, Seattle 98195.
authors.forename: K A
authors.initials: KA
authors.lastname: Mulligan
authors.forename: J F
authors.initials: JF
authors.lastname: Van Brederode
authors.forename: R
authors.initials: R
authors.lastname: Mehra
authors.forename: A E
authors.initials: AE
authors.lastname: Hendrickson
mesh_terms: D000818:Animals; D000911:Antibodies, Monoclonal; D016650:Fluorescein-5-isothiocyanate; D005455:Fluorescent Antibody Technique; D007150:Immunohistochemistry / Q000379:methods*; D037102:Lectins; D008252:Macaca fascicularis; D008254:Macaca nemestrina; D008854:Microscopy, Electron; D037121:Plant Lectins; D013373:Substance P / Q000032:analysis*; D014793:Visual Cortex / Q000737:chemistry / Q000648:ultrastructure*
chemical_list: D000911:Antibodies, Monoclonal; D037102:Lectins; D037121:Plant Lectins; C042242:Vicia lectins; D013373:Substance P; D016650:Fluorescein-5-isothiocyanate