Biochemistry and Biology of the Langerhans Cell

Identification and expression analysis of Langerhans cells marker Langerin/CD207 in grasscarp, Ctenopharyngodon idella

Langerhans cells (LCs) play an essential role in the initiation of immune response and maintenance of immune tolerance. However, the function and the molecular markers of grass carp LCs remains unclear. The grass carp LCs were firstly identified by immunofluorescence (IF) using a commercial anti-human Langerin/CD207 polyclonal antibody (pAb) and transmissionelectronmicroscope (TEM) technology in this study. After that, a cDNA sequence that homology with human and mouse CD207 gene was obtained by the bBLASTn program in NCBI. The open reading frame (ORF) of the grass carp CD207 gene contains 903 bp encoding 300 amino acids which consisted of a transmembrane domain, a coiled-coil domain and a CLECT domain. Furthermore, the result of quantitative real-time PCR (qRT-PCR) indicated that this gene was expressed in all tested tissues, and mainly expressed in immune organs such as the gill, trunk kidney, head kidney, spleen and skin. To explore the role of CD207 gene in the immune responses induced by bacteria, an immersed infection model of grass carp with Flavobacterium columnare was constructed, and the optimal infection dose was determined to be 1.0 × 10⁸ CFU/mL. Moreover, the qRT-PCR results indicated that the expression levels of CD207 gene were significantly upregulated at 6 h, 12 h, 1 d, 3 d and 7 d in the spleen, and significantly downregulated at 5 d in the head kidney, at 12 h and 5 d in the gill, and at all time points in the skin after F. columnare infection. This result suggested that the grass carp CD207 gene may play an important role in antigen processing and presentation. Our results in this study suggested that CD207 gene is also existed in teleosts, and this study provided a molecular basis to analyzed the biological function of grass carp CD207 gene and the critical roles of LCs in the immune responses induced by bacterial infections.

IL-13 induces CD34+ cells isolated from G-CSF mobilized blood to differentiate in vitro into potent antigen presenting cells

Dendritic cells (DCs), which are antigen presenting cells of potential use in human antitumor vaccination trials, are presently the subject of intense investigation. Many recent studies have reported the possibility of generating ex vivo large numbers of DCs with high antigen presenting capacity by the culture of bone marrow or blood progenitors. In this study, we examined the differentiation into DCs of CD34+ progenitors isolated from the G-CSF mobilized blood of 3 healthy donors and 5 patients with breast cancer and cultured in the presence of GM-CSF + IL-13. The characteristics of the cells were compared to those of cells obtained in the presence of GM-CSF + TNF alpha. By day 15, one third of the bulk cells cultured with IL-13 were CD1a+/CD14- and strongly expressed CD1c, CD40, CD80 and HLA-DR. In contrast, cells obtained with TNF alpha expressed CD1a on one in three cells but with a considerably lower fluorescence intensity than on IL-13-cultured cells and strongly expressed CD14 on more than 50% of cells. CD1a+/CD14- cells emerged in IL-13 cultures at day 5, while in TNF alpha cultures CD14+ cells appeared before CD1a+ cells. Cells grown in the presence of IL-13 had an increased capacity to present antigens to autologous lymphocytes and to stimulate allogeneic T-lymphocytes. This effect was greater than that of cells grown in the presence of TNF alpha. These cells should therefore have greater effector potential in any therapeutic applications in humans.

Langerhans cell (eosinophilic) granulomatosis. A clinicopathologic study encompassing 50 years

We summarize our experience with 238 cases of Langerhans cell granulomatosis (LCG), 198 of whom were followed for a median period of 10.5 years. Our patients did well unless overtreated, and no deaths were attributed to the disorder itself. The disease may appear in unifocal or multifocal form, and treatment is based on this fact. Virtually all patients recovered completely except for occasional residual orthopedic problems or residual diabetes insipidus. Several of the patients underwent subsequent pregnancies without difficulty. The granulomas primarily occur in bone, but lung, skin, and lymph nodal involvement is not uncommon. Involvement of thyroid, thymus, and other sites is rare. The hallmark of the disease is the accumulation of Langerhans cells (LCs). We review the pathology of LCG by histology, electron microscopy, and immunolabeling. LCs originally were identified in squamous epithelium, but these cells are part of the widespread system of dendritic cells. The latter cells, which arise from CD34+ progenitors, are specialized and efficient antigen-presenting cells for T-cell-mediated immunity. In LCG, however, the major associated cells are not T cells, but mature eosinophils: hence the original name eosinophilic granuloma. Confusion about terminology has been based upon the scanty and rather crude pathology reports in the original literature. The term histiocytosis X was meant to cover a spectrum of three diseases--eosinophilic granuloma, Hand-Schüller-Christian disease (HSC), and Letterer-Siwe disease (LS)--but HSC and LS have no basis in pathology and hence the terms are meaningless. The term HSC has become a synonym for multifocal eosinophilic granuloma (LCG). The term LS has been used in reporting a number of benign, malignant, or unknown conditions. We prefer the term LCG to avoid confusion with the term histiocytosis X because there is evidence that the LC is not a member of the mononuclear phagocyte system and hence not a tissue macrophage, and because the use of the term "histiocyte" has become a convenience in much of the literature when reporting incompletely understood diseases.

Etoposide in Langerhans cell histiocytosis in children: a preliminary experience

Treatment of Langerhans cell histiocytosis (LCH) is yet to be established. We treated seven patients with etoposide alone at a dose of 100 mg/m2/day for 3 days given every 3 to 4 weeks for six cycles. Three patients had received prior chemotherapy, two patients were less than 2 years of age, and two had liver dysfunction. A positive response to therapy was seen in five patients. There was no major toxicity. Etoposide therapy is safe and effective in the treatment of LCH.

Langerhans cell histiocytosis in monozygotic twins

Langerhans cells histiocytosis, one of a group of histiocytosis syndromes characterized by Langerhans cell infiltration, has many clinical manifestations. In the past 30 years, numerous cases of presumed Letterer-Siwe disease, the acute multiorgan variant, have been reported in twins and siblings. Only recently has the Histiocyte Society established a criterion for a "definitive diagnosis" of Langerhans cell histiocytosis--the presence of Birbeck granules within the cells of the histiocytic infiltrate. We report the fatal outcome of Langerhans cell histiocytosis in monozygotic twin infants. There is no satisfactory explanation why Langerhans cell histiocytosis occurs concurrently in twins. We suggest that cytokines may provide an endogenous signal that triggers the pathologic proliferation of Langerhans cells.