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Demonstration of IgE low affinity Fc receptor (CD23) on normal human epidermal Langerhans cells
1Istituto di Clinica Dermosifilopatica, Università degli Studi di Parma.
Insights
Normal human Langerhans cells (LC) constitutively express the low-affinity receptor for IgE (Fc epsilon RII/CD23). This finding suggests a role for Fc epsilon RII/CD23 in LC antigen presentation.
Area of Science:
- Immunology
- Dermatology
- Cell Biology
Background:
- Immunoglobulin E (IgE) molecules are found on Langerhans cells (LC) in atopic dermatitis skin.
- The specific receptor involved in IgE binding to LC remains unclear.
- Leukocytes, including epidermal Langerhans cells, are known to express the low-affinity IgE receptor, Fc epsilon RII/CD23.
Purpose of the Study:
- To investigate the expression of Fc epsilon RII/CD23 on Langerhans cells from normal human subjects.
- To clarify the receptor responsible for IgE interaction with Langerhans cells.
Main Methods:
- Utilized a double-step gold immunoelectron microscopy (IEM) technique.
- Employed an anti-CD23 monoclonal antibody (MoAb) for detection.
- Analyzed Ficoll-Hypaque isolated, LC-enriched epidermal cell suspensions from normal human skin.
Main Results:
- Gold particles, indicating Fc epsilon RII/CD23 presence, were observed on the surface of cells with Langerhans cell morphology.
- This study unequivocally demonstrates constitutive expression of Fc epsilon RII/CD23 on normal human Langerhans cells.
- Previous investigations using anti-IgE MoAb suggested normal LC were IgE-negative.
Conclusions:
- Normal human Langerhans cells constitutively express Fc epsilon RII/CD23.
- Given the established role of LC in antigen presentation and the known association between CD23 and HLA-DR, Fc epsilon RII/CD23 may play a role in antigen presentation by LC.
Abstract:
In previous studies, IgE molecules were detected along the cell membrane of Langerhans cells (LC) in atopic dermatitis involved skin. However, the exact nature of the receptor still remains obscure. Moreover, large subsets of leukocytes have been recently shown to express the low affinity receptor for the Fc portion of IgE (Fc epsilon RII/CD23). Since LC are epidermal leukocytes the present study was intended in order to verify if LC of normal human subjects express the Fc epsilon RII/CD23. An anti-CD23 monoclonal antibody (MoAb) was used in a double step gold immunoelectron microscopical (IEM) procedure, carried out on Ficoll-Hypaque LC-enriched epidermal cell suspensions, freshly isolated from midly trypsinized normal human skin. Cells with LC features showed gold particles on their surface. Up to now LC from normal human epidermis, investigated using MoAb against human IgE, apparently were IgE-negative. Here we inequivocally demonstrate that the Fc epsilon RII/CD23 is constitutively expressed by normal human LC. It is well known that LC play an important role in antigen presentation. Further, it has been previously described the existence of a steric relationship between CD23 and HLA-DR molecules. Therefore, the present data add further strength to the hypothesis that FC epsilon RII/CD23 could participate to antigen presentation phenomena.