title: In situ evidence that the population of Langerhans cells in normal human epidermis may be heterogeneous.
abstract: Epidermal Langerhans cells (LC) may occur in subsets with different phenotypic and functional characteristics. In this work give further evidence that the CD1a-positive LC population in the normal human epidermis may be heterogeneous. We found that one of our monoclonal antibodies (TE4B) to stratum corneum chymotryptic enzyme (SCCE) stained a population of dendritic cells in the normal epidermis in addition to high suprabasal keratinocytes. The staining of the dendritic cells was seen only when the biopsies had been fixed with formaldehyde and when the sections had been pretreated, either with proteolytic enzymes or with Triton X-100. The binding of the antibody was mediated through its antigen binding site, as it could be inhibited by adsorption with recombinant pro-SCCE. Experiments with double labelling showed that the TE4B-positive dendritic cells were also CD1a-positive. On the other hand, not all CD1a-positive cells were TE4B-positive. By means of confocal microscopy of double-labelled cells, the TE4B binding site could be localized intracellularly. SCCE-mRNA could be detected by in situ hybridization in high suprabasal keratinocytes only. A possible explanation may be that there is a subset of LC which have taken up SCCE secreted by high suprabasal keratinocytes. Alternatively, TE4B may bind to an epitope present in a subgroup of epidermal LC which cross-reacts immunologically with SCCE. It is suggested that the demonstrated heterogeneity of the population of LC in the normal epidermis should be taken into account in studies on the possible role of epidermal autoantigens in the development of immune-mediated skin diseases.
authors.affiliation: Department of Dermatology, Umeå University, Sweden.
authors.forename: B
authors.initials: B
authors.lastname: Sondell
authors.forename: M
authors.initials: M
authors.lastname: Jonsson
authors.forename: P
authors.initials: P
authors.lastname: Dyberg
authors.forename: T
authors.initials: T
authors.lastname: Egelrud
mesh_terms: D018949:Antigens, CD1 / Q000032:analysis; D015415:Biomarkers / Q000032:analysis; D000078404:Epidermal Cells; D004817:Epidermis / Q000201:enzymology; D005260:Female; D005455:Fluorescent Antibody Technique; D006801:Humans; D007124:Immunoenzyme Techniques; D017403:In Situ Hybridization; D007610:Kallikreins; D007801:Langerhans Cells / Q000145:classification* / Q000201:enzymology; D008297:Male; D012697:Serine Endopeptidases / Q000032:analysis
chemical_list: D018949:Antigens, CD1; D015415:Biomarkers; C082472:KLK7 protein, human; D007610:Kallikreins; D012697:Serine Endopeptidases