Langerhans cells are dendritic antigen-presenting cells residing predominantly in the epidermis. Since endogenous galactoside-binding lectins with the jelly-roll motif (galectins) are known to trigger cellular responses, including mediator release, we investigated by lectin histochemistry the cells' capacity to bind two common members of this family, i.e. galectin-1 and -3. Actually, surrounding keratinocytes express a high level of galectin-3, and these cells can be considered as donors of this lectin to Langerhans cells. Employing biotinylated galectin-1 and -3, and concomitantly an antibody against CD1a as a second marker, to visualize the position of Langerhans cells in the human epidermis, the expression of galectin-3-reactive glycoligands in contrast to the lack of binding of galectin-1 was observed. Although the functional consequences of this selectivity are unclear, these results reveal an example for differential cellular reactivity towards two related endogenous lectins.

Charles University 1st Faculty of Medicine Institute of Anatomy Prague Czech Republic

Human galectin‑3: Molecular switch of gene expression in dermal fibroblasts in vitro and of skin collagen organization in open wounds and tensile strength in incisions in vivo

Analysis of binding of mannosides in relation to Langerin (CD207) in Langerhans cells of normal and transformed epithelia