title: Cholera toxin B subunit-binding and ganglioside GM1 immuno-expression are not necessarily correlated in human salivary glands.
abstract: OBJECTIVE
  To determine and compare the presence and in situ localization of the glycosphingolipid ganglioside GM1 in human salivary glands using the biomarkers for GM1: cholera toxin and antibodies against GM1.
  
  
  METHODS
  Immunohistochemical analyses were performed on sections of adult human submandibular, parotid and palatinal glands using cholera toxin sub-unit B and two polyclonal antibodies against ganglioside GM1 as biomarkers.
  
  
  RESULTS
  Immunofluorescence microscopy showed that the toxin and antibodies were co-localized in some acini but not in others. The cholera toxin mainly reacted with the cell membranes of the mucous acini in the submandibular gland, while incubation with the antibody against GM1 gave rise to a staining of the cytoplasm. The cytoplasm in some secretory acinar cells in the parotid gland was stained by the cholera toxin, whereas only small spots on the plasma membranes reacted with anti-GM1. The plasma membranes in the parotid excretory ducts appeared to react to anti-GM1, but not to cholera toxin.
  
  
  CONCLUSIONS
  Cholera toxin induces the expression of ion channels and carriers in the small intestine and increases the production of secretory mucins. Although their mutual immunohistochemical localization may differ, both cholera toxin and ganglioside GM1 are present in the mucin-producing acini from salivary glands. This could point to a relationship between ganglioside expression and production of salivary mucins.
authors.affiliation: Dental School, University of Copenhagen , Copenhagen , Denmark.
authors.forename: Svend
authors.initials: S
authors.lastname: Kirkeby
mesh_terms: D000328:Adult; D000906:Antibodies; D015415:Biomarkers; D002102:Cadaver; D002462:Cell Membrane / Q000737:chemistry / Q000648:ultrastructure; D002772:Cholera Toxin; D003593:Cytoplasm / Q000737:chemistry / Q000648:ultrastructure; D005677:G(M1) Ganglioside / Q000032:analysis*; D006801:Humans; D007150:Immunohistochemistry; D008856:Microscopy, Fluorescence; D009077:Mucins / Q000737:chemistry; D010306:Parotid Gland / Q000737:chemistry / Q000166:cytology; D018987:Salivary Ducts / Q000737:chemistry / Q000166:cytology; D012469:Salivary Glands / Q000737:chemistry* / Q000166:cytology; D012470:Salivary Glands, Minor / Q000737:chemistry / Q000166:cytology; D012704:Serous Membrane / Q000737:chemistry / Q000166:cytology; D013363:Submandibular Gland / Q000737:chemistry / Q000166:cytology
chemical_list: D000906:Antibodies; D015415:Biomarkers; D009077:Mucins; D005677:G(M1) Ganglioside; D002772:Cholera Toxin
keywords: cholera toxin; ganglioside GM1; salivary glands