Jana Hercogova4, Sem Saeland6, Nicolai V. Bovin7 & Hans-Joachim Gabius8. 1 Institute of ..... Kiuin PM, Koning F (1999) Human epidermal Langerhans cells.
The Histochemical Journal 34: 247-253, 2002. @ 2002 Kluwer Academic Publishers. Printed in the Netherlands.
Analysis of binding of mannosidesin relation to Langerin (CD207) in Langerhans cells of normal and transformed epithelia Jan Plzak1,z,Zuzana Holikova1,3,4,Barbora Dvorankova3,S,Karel Smetana, Jr.l,3,.,Jan Betkaz, Jana Hercogova4, Sem Saeland6,Nicolai V. Bovin7 & Hans-Joachim Gabius8 1Institute of Anatomy, zDepartment of Otorhinolaryngology, Head and Neck Surgery, 1st Faculty of Medicine, 3Center of Cell Therapy and Tissue Repail; 4Department of Dermatovenerology, 2nd Faculty of Medicine, SDepartment of Bum Surgery, 3rd Faculty of Medicine, Charles University, Prague, CzechRepublic 6Schering-Plough, Laboratory for Immunological Research, Dardilly, France 7Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences,Moscow, Russia 8Institute for Physiological Chemistry, Faculty of Veterinary Medicine, Ludwig-Mdximilians-University Munich, Munich, Germany *Author for correspondence Received 19 Apri12002 and in revised foml19 August 2002
Summary Tandem-repeatC-type lectins (pattern-recognition receptors) with specificity for mapnosides are intimately involved in antigert recognition, uptake, routing and presentation in macrophages and dendritic cells. In Langerhans cells, Langerin (CD207), a type-II transmembrane protein with a single C-type carbohydrate recognition qomain attached to a heptad repeat in the neck region, which is likely to establish oligomers with an a-coiled-coil stalk, has been implicated in endocytosis and the formation of Birbeck granules. The structure of Langerin harbours essential motifs for Ca2+-binding and sugar accommodation. In view of the complexity of the C-type lectinllectin-like network, it is unclear what role Langerin plays for Langerhans cells in binding mannosides. In order to reveal in frozen tissue sections to what extent mannose-binding activity co-localizes with Langerin, we have used a synthetic marker, i.e. a neoglycoprotein carrying mannose maxiclusters, as a histochemical ligand, and computer-assisted fluorescence monitoring in a double-labelling procedure. Mannoside-binding capacity was detected in normal epithelial cells. Double labelling ensured the unambiguous assessmentof the binding of the neoglycoprotein in Langerhans cells. Light-microscopically, its localization profile resembled the pattern of immunohistochemical detection of Langerin. This result has implications for suggesting rigorous controls in histochemical analysis of this cell type, because binding of kit reagents, i.e. mannose-rich glycoproteins horseradish peroxidase or avidin, to Langerin (or a spatially closely associated lectin) could yield false-positive signals. To show that recognition of carbohydrate ligands in dendritic cells is not restricted to fIlannose clusters, we have also documentedJbinding of carrier-immobilized histo-blood group A trisaccharide, a igand of galectin-3, which was not affected by the presence of a blocking antibody to Langerin. Remarkably, access to the carbohydrate recqgnition domain of Langerin appearedto be impaired in proliferatively active environments (malignancies, hair follicles), indicaqng presence of an endogenous ligand with high affinity to saturate the C-type lectin under these conditions.~
Introduction Langerhanscells (LC) are membersof the myeloid-type family of dendritic, professionalantigen-presentingcells. They are presentpredominantlyin epithelia,with their dendritic mbrphologyand expressionof distinctmarkerssuchas CD la, servingas characteristicattributes(Kanitakis 1998). In terms of reliability to identify LC, Birbeck granulesrepresentorganellesexclusivelyfound in this cell type (Fujita et al. 1990). Functionally,LC sharewith macrophagesthe capacityto bind and internalize mannoseresiduespresentedin maxiclusters for the surface coat of bacteria or yeast cells,
although LC lack the typical tandem-repeat-type 175 ilia macrophage receptor (CD206) (Reis e Souza et aI. 1993, Engering et aI. 1997, Noorman et aI. 1997, Condaminet et aI. 1998, Mommaas et aI. 1999, Kato et aI. 2000). Reflecting the remarkable diversity of C-type lectins and genomic abundance of C-type lectin-like domains it is reasonableto assume that this function could well be taken over by other family members (Gabius 1997, 2000, Figdor et aI. 2002). Their detection and cell biological characterization could not only define new LC markers but also point to ways to independently target macrophages and LC via cell-type-specific endocytic receptors, for example to fav°U!ably modulate their i~une functions (Gabius 1991, Andre et aI. 2000,
248 Yamazaki et ai. 2000, Grandjean et ai. 2001). Fittingly, rapid and efficient endocytic uptake of a LC-specific monoclonal antibody led to the expression cloning of the cDNA of Langerin (CD207), a candidate for a functional substitute of the tandem-repeat-type C-type lectin (Valladeau et ai. 1999, 2000, 2002). Based on its sequence, Langerin (CD207) is a type-II transmembrane protein with a distal single carbohydrate recognition domain linked to a neck region with potential to form an a-coiled-coil stalk, the transmembrane domain and a proline-rich motif in the 43 aa-long intracellular section resembling sites for interaction with SH3 domain proteins (Valladeau et ai. 2000, 2002). In mouse organs, dendritic cells of lymphoid tissues are also Langerin-positive (Langerin+), and this molecule was shown to participate in establishing Birbeck granules including their transformation to structures resembling cored tubules after a mutational substitution in the lectin (Phe344Leu) (Valladeau et ai. 2000, 2002). In addition to the presence of Langerin it was recently shown by immuno- and glycohistochemistry that a member of another lectin family, i.e. galectin-3 (Gal-3), which has functions as cell-
