title: Immunocytochemistry by electron spectroscopic imaging using a homogeneously boronated peptide.
abstract: A linear all-L-oligopeptide containing five carboranyl amino acids (corresponding to 50 boron atoms) was synthesized and specifically attached to the free thiol group of monovalent antibody fragments F(ab)'. The boronated immunoreagent was used for the direct post-embedding detection of somatotrophic hormone in ultrathin sections of porcine pituitary embedded in Spurr resin. The specific boron-labelling of secretory vesicles in somatotrophs was detected by electron spectroscopic imaging and confirmed by conventional immunogold labelling run in parallel. In comparison with immunogold, boron-labelled F(ab)'-fragments showed higher tagging frequencies, as was expected; the small uncharged immunoreagents have an elongated shape and carry the antigen-combining structure and the detection tag at opposite ends, thus allowing for high spatial resolution in electron spectroscopic imaging.
authors.affiliation: Max-Planck-Institut für Experimentelle Endokrinologie, Hannover, Germany.
authors.forename: M M
authors.initials: MM
authors.lastname: Kessels
authors.forename: B
authors.initials: B
authors.lastname: Qualmann
authors.forename: F
authors.initials: F
authors.lastname: Klobasa
authors.forename: W D
authors.initials: WD
authors.lastname: Sierralta
mesh_terms: D000818:Animals; D015415:Biomarkers / Q000032:analysis; D001895:Boron; D004577:Electron Probe Microanalysis; D013006:Growth Hormone / Q000032:analysis / Q000737:chemistry; D007091:Image Processing, Computer-Assisted; D007128:Immunoglobulin Fragments / Q000737:chemistry; D007150:Immunohistochemistry / Q000295:instrumentation / Q000379:methods*; D008854:Microscopy, Electron / Q000379:methods*; D010455:Peptides / Q000138:chemical synthesis / Q000737:chemistry / Q000276:immunology; D010902:Pituitary Gland / Q000737:chemistry / Q000166:cytology; D013552:Swine
chemical_list: D015415:Biomarkers; D007128:Immunoglobulin Fragments; D010455:Peptides; D013006:Growth Hormone; D001895:Boron