Chemistry of the Peptide Components of Glycoprotein Hormones
B.A. Keel in Microheterogeneity of Glycoprotein Hormones, 1989
There have been several reviews of the glycoprotein hormone structures. The review by Ward 1 was directed at functional group substitutions in order to pinpoint essential structural elements. The review by Pierce and Parsons2 dealt with structural relationships and considered the then-available recombinant DNA studies on this group of hormones. Gordon and Ward3 provided an update on functional group studies, but limited it to the hormones interacting with the luteinizing hormone (lutropin, LH) receptor. In the same volume, Strickland et a1. 4 updated structural information on LH and human (h) chorionic gonadotropin (choriogonadotropin, CG). Bahl and WaghS reviewed the carbohydrate structures of the glycoprotein hormones. Fiddes and Talmadge6 reviewed the gene structure and evolution of the human glycoprotein hormones.
Orthoclone OKT-3
Stefania Spada, Gary Walsh in Directory of Approved Biopharmaceutical Products, 2004
Description: Orthoclone OKT-3 is an intact murine monoclonal antibody produced by classical hybridoma technology. The antibody binds specifically to a 20-kDa surface glycoprotein found exclusively on the surface of mature T lymphocytes and medullary thymocytes. This surface glycoprotein is also known as the CD-3 receptor, and binding of antibody hinders cellular functioning by interfering with cell-mediated immune responses. Particularly affected is the functioning of cytotoxic T lymphocytes that are involved in the recognition and destruction of foreign antigens, such as those involved in mediating acute allograft rejection. Orthoclone OKT-3, which was the first monoclonal antibody to be approved for in υiυo use, is generally supplied in packages of five ampules. Each 5-ml ampule contains 5 mg of active ingredient.
Lectin
Masahiko Mori in Histochemistry of the Salivary Glands, 2019
Lectin is a glycoprotein isolated from plants and animals and specifically binds to corresponding sugar residues in complex carbohydrates of tissue sections. Lectin histochemistry has been widely used in histology, pathology, and salivary gland research for detection of specific sugar residues. There are three techniques: direct method, direct antibody-lectin method, and indirect antibody-lectin method. For positive controls, many epithelial and glandular tissues such as squamous cell epithelium of oral mucosa, esophagus or skin, and kidney may be used for many lectins. Lectin binding patterns of salivary glands were different in serous and mucous acinar cells, granular convoluted tubule cells, and striated duct cells of mice and rats when the same fixative was used. Lectin binding affinities in serous acinar cells of the parotid gland were relatively stronger than those in mucous cells of sublingual glands. Binding affinities of lectin- Horseradish Peroxidase conjugates in salivary gland tissues were enhanced following digestion with amylase, sialidase, and trypsin.
Verapamil Induces Upregulation of P-glycoprotein Expression on Human Monocyte Derived Dendritic Cells
Published in Immunological Investigations, 2006
Raj K. Ishri, Scott Menzies, Gary M. Halliday
Overexpression of P-glycoprotein, a transmembrane drug efflux pump that mediates efflux of chemotherapeutic agents contributes to drug resistance in many leukaemia and other cancerous cells. Non-malignant cells including leukocytes also express P‐glycoprotein, but physiologic functions for P-glycoprotein are poorly defined. Recently, P-glycoprotein expression has been described in human mononuclear phagocytes and Langerhans cells. It has been shown to play a role in phagocytic cell transmigration through endothelial-lined vessels in an ablumenal-lumenal direction, a process that mimics their migration into lymphatic vessels. Using the monoclonal antibody 4E3, and the P-glycoprotein antagonist, verapamil, the expression of P-glycoprotein on human monocyte-derived dendritic cells was evaluated. Dendritic cells used in this study were CD1a+, CD11c+, CD14−, CD80+, CD83+, CD86+ and MHC-IIHigh. The expression of these markers increased significantly as the cells matured. P-glycoprotein expression was upregulated as the dendritic cells matured as well as in the presence of the “inflammatory stress” of the pathogenic bacteria Strept. pyogenes. Addition of verapamil or Strept. pyogenes to the culture medium during the final 24 hours significantly upregulated P-glycoprotein expression. Immortalized cell lines did not upregulate P‐glycoprotein in the presence of verapamil. Evaluation of other normal cells showed that P-glycoprotein upregulation in the presence of verapamil was also a characteristic of macrophages. This novel observation of the upregulation of P-glycoprotein in the presence of verapamil appears to be a characteristic of activated myeloid derived antigen presenting cells and suggest that P-glycoprotein is essential for these cells as when it is blocked, they respond by increasing expression of this protein. In summary, this work describes that human dendritic cells generated from plastic-adherent monocytes rapidly upregulate expression of P-glycoprotein as they mature, and in the presence of inflammatory stress and the pharmacological agent verapamil, which blocks P-glycoprotein activity, suggesting that P-glycoprotein may play a role in activation as well as in migration of dendritic cells.
Lymphocyte Stimulation by a Mammary Carcinoma Associated Glycoprotein
Published in Immunological Communications, 1975
A glycoprotein was isolated from 3M KC1 extracts of mammary carcinoma. Addition of an optimal amount of the carcinoma associated glycoprotein induces proliferation of both peripheral blood lymphocytes from normal donors and from patients with mammary carcinoma. RNA-dependent DNA-polymerase levels were found to be markedly increased in glycoprotein-untreated lymphocytes from patients with mammary carcinoma and in glycoprotein-treated lymphocytes of both normal donors and tumor-bearing patients. A factor (“Blocking Factor”) was eluted at pH 3.1 from the cell membrane of the mammary carcinoma cells. Addition of an optimal amount of this factor inhibits the glycoprotein induced stimulation of the RNA-dependent DNA-polymerase activity in glycoprotein-treated lymphocytes of both normal donors and tumor-bearing patients.
The clinical significance of circulating B cells secreting anti-glycoprotein IIb/IIIa antibody and platelet glycoprotein IIb/IIIa in patients with primary immune thrombocytopenia
Published in Hematology, 2012
Jian-fang Chen, Lin-hua Yang, Li-xian Chang, Jian-jun Feng, Jun-qing Liu
Objectives The objective of the study is to evaluate the possible roles of the detection of circulating B cells secreting anti-glycoprotein IIb/IIIa antibody, platelet glycoprotein IIb/IIIa, and anti-glycoprotein IIb/IIIa antibody in the diagnosis of primary immune thrombocytopenia (ITP) patients. Methods Circulating B cells secreting anti-glycoprotein IIb/IIIa antibody, platelet glycoprotein IIb/IIIa and anti-glycoprotein IIb/IIIa antibody in 64 patients with ITP, 33 non-ITP patients, and 32 controls were measured with enzyme-linked immunospot assay (ELISPOT), monoclonal antibody immobilization of platelet antigens assay (MAIPA) and flow cytometic analysis (FCM), respectively. Results Compared with the controls and non-ITP patients, the frequency of circulating B cells secreting anti-glycoprotein IIb/IIIa antibody was significantly increased, whereas the positive rate of platelet glycoprotein IIb/IIIa was significantly decreased (P < 0.05) in ITP patients, respectively. The sensitivities for the diagnosis of ITP of ELISPOT and FCM were 68.8% and 57.8%, and the specificities of 90.9% and 90.9%, respectively. The sensitivities of ELISPOT and FCM were higher than MAIPA's sensitivity (39.1%) (P < 0.05). However, there was no apparent difference of the sensitivities of ELISPOT and FCM and the specificities of those three detections (MAIPA's specificity was 81.8%) (P > 0.05). Discussion ELISPOT and FCM for detecting the circulating B cells secreting anti-glycoprotein IIb/IIIa antibody and the platelet glycoprotein IIb/IIIa were as specific as that of MAIPA for assay of anti-glycoprotein IIb/IIIa antibody, but ELISPOT and FCM had higher sensitivities. So ELISPOT and FCM were sensitive and specific for identifying patients with autoantibody-mediated thrombocytopenia and these should be used as diagnostic tests in clinic.
Related Knowledge Centers
- Peptide
- Glycosylation
- Oligosaccharide
- Posttranslational Modification