Murine epidermal Langerhans cells do not express the low-affinity receptor for immunoglobulin E, FcεRII (CD23)

Abstract

The low-affinity receptor for IgE, FcεRII (CD23), plays an important role in IgE-mediated disorders such as allergy, atopy, and parasitic infections, In humans, the FcεRIIb isoform on epidermal Langerhans cells is thought to be an important accessory molecule in the allergen-specific T cell activation in atopic dermatitis, Since considerable knowledge about the accessory function of Langerhans cells for T-cell activation stems from mouse models, and since an IgE-bearing Langerhans cell mouse model would be useful in studying the pathophysiology-of atopic dermatitis, we determined whether FcεRII was also present on murine Langerhans cells, FcεRIIa, which is the major FcεRII isoform in mice, was found to be constitutively expressed on spleen cells from normal mice but was not present on epidermal Langerhans cells. When interleukin-4, a known inducer of FcεRII, was administered in vivo, FcεRII-specific mRNA and protein was significantly upregulated in spleen cells but not in Langerhans cells. De novo synthesis of FcεRII was also induced in vitro by interleukin-4 on spleen cells, but not on epidermal cells. The presence of a recently cloned murine counter-part to the human FcεRIIb isoform on murine Langerhans cells could also be excluded on the protein and mRNA level because of the high degree of homology to mouse FcεRIIa. Taken together the data indicate that murine epidermal Langerhans cells do not express the low-affinity receptor for IgE.