title: A comparative study on tissue processing procedures for the immunohistochemical investigation of oral mucosal Langerhans cells.
abstract: An immunoperoxidase technique was used to compare wax-embedded tissue with frozen tissue for quantitative immunohistochemistry of oral mucosal Langerhans cells. Initial experiments using anti-CD1a, -HLADR and -S100 antisera showed that phenotype, fixative, antibody dilution and trypsinisation of the tissue section significantly affected Langerhans cell counts. Only the anti-HLADR antibody detected Langerhans cells in both frozen and wax-embedded sections. Some 38% of S100-positive dendritic cells were situated in the stratum basale, and 41-84% of these contained melanin as determined by double-labelling. Sections from 39 volunteers were then reacted with the anti-CD1a and -HLADR antibodies. The morphology of Langerhans cells was more dendritic in frozen sections, and the mean HLADR-positive Langerhans cells count in frozen sections was significantly higher than that in wax-embedded sections from the same individual. The intra-individual ratio of counts between frozen and wax-embedded sections was variable; hence, the apparent loss of HLADR antigenicity as a result of tissue processing was unpredictable. Counts of CD1a-positive Langerhans cells were consistently higher. We conclude that the use of anti-CD1a antibody on frozen tissue is the optimum method for quantitative studies of oral mucosal Langerhans cells, and that such studies performed on wax-embedded tissue may be unreliable.
authors.affiliation: Department of Oral Biology, University of Newcastle-upon-Tyne, UK.
authors.forename: A W
authors.initials: AW
authors.lastname: Barrett
authors.forename: A D
authors.initials: AD
authors.lastname: Beynon
authors.forename: D J
authors.initials: DJ
authors.lastname: Reid
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D015703:Antigens, CD / Q000032:analysis; D018949:Antigens, CD1; D002648:Child; D002675:Child, Preschool; D005260:Female; D005629:Frozen Sections; D006684:HLA-DR Antigens / Q000032:analysis; D006801:Humans; D007150:Immunohistochemistry; D007223:Infant; D007231:Infant, Newborn; D007801:Langerhans Cells / Q000737:chemistry / Q000166:cytology*; D008297:Male; D008875:Middle Aged; D009061:Mouth Mucosa / Q000166:cytology*; D009418:S100 Proteins / Q000032:analysis; D016610:Tissue Embedding; D014021:Tissue Preservation
chemical_list: D015703:Antigens, CD; D018949:Antigens, CD1; D006684:HLA-DR Antigens; D009418:S100 Proteins