Appearance of Birbeck granule-like structures in anti-T6 antibody-treated human epidermal Langerhans cells.
We have previously demonstrated by immunogold labeling techniques that the T6 surface antigen of living human Langerhans cells (LC) of the skin is internalized by a process of receptor-mediated endocytosis (RME). Receptor-mediated endocytosis induced by the binding of the monoclonal anti-T6 antibody BL6 involves coated pits, coated vesicles, endosomes, the smooth endoplasmic reticulum, and lysosomes. After RME, gold-labeled Birbeck granules (BGs) appear in the cell center. In the present study, by modifying the experimental conditions but retaining the presence of gold-labeled BL6, we have observed (in addition to the above-mentioned gold-labeled organelles) images that appear to correspond to BG-like structures. These structures, like the intracytoplasmic BGs, are pentalaminar and gold-labeled, but they differ from the intracytoplasmic BGs by their attachment to the cell membrane, their length, the frequent presence of a coat, and by prolongation by one or more coated pits. Birbeck granule-like structures seem to result, at the ultrastructural level, from receptor ligand interactions and from modifications of the LC shape.
Hanau
D
D
INSERM U.311, Université Louis Pasteur, France.
Fabre
M
M
Schmitt
D A
DA
Garaud
J C
JC
Pauly
G
G
Cazenave
J P
JP
D000945:Antigens, Differentiation, T-Lymphocyte / Q000276:immunology*; D003594:Cytoplasmic Granules / Q000648:ultrastructure*; D006046:Gold; D006801:Humans; D007801:Langerhans Cells / Q000648:ultrastructure*
D000945:Antigens, Differentiation, T-Lymphocyte; D006046:Gold