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Affinity chromatography of human plasma on placental-alkaline-phosphatase-Sepharose columns (placental alkaline phosphatase, PLAP) yielded consistently a pure protein which was identified as IgG on the basis of electrophoretical and immunological comparisons with authentic human IgG. SDS/PAGE of the protein revealed, under reducing conditions, two(More)
The biological function(s) of placental alkaline phosphatase has not yet been unraveled. The low catalytic activity of the enzyme at physiological pH, and the lack of "natural substrates", bring about the necessity of a more structure-related conception of its role. We have observed an interaction between placental alkaline phosphatase and human IgG. In(More)
Pure clathrin-coated vesicles were prepared from a fresh human placenta. The analysis of their content revealed the presence of transferrin, low density lipoproteins, IgG and placental alkaline phosphatase. Since the latter is a membrane protein anchored by a glycan-phosphatidyl inositol (GPI) moiety, its presence in coated vesicles was unexpected.(More)
Using alkaline phosphatase isozyme-specific immunocatalytical assays, the content of isozymes was determined in normal mucosas and adenocarcinomas from human colon or rectum. Tumor levels of both the tissue (liver)-unspecific and the placental-like alkaline phosphatase (PLAP-like) were elevated compared to normal mucosas of the same patients. Such(More)
The radioimmunotherapeutic potential of 131I-labeled monoclonal antibodies was investigated in 36 nude mice (BALB/c nu/nu) inoculated s.c. with the HeLa Hep 2 human adenocarcinoma cell line. The membrane bound tumour associated antigen placental alkaline phosphatase and several intracellular cytokeratins served as targets for the antibodies. The specific(More)
Radioimmunoscintigraphy (RIS) was performed in 20 patients with gynecologic tumors, 14 ovarian, 5 cervical, and one endometrial carcinoma. One murine monoclonal antibody (mab) against placental alkaline phosphatase (H7) was used after radiolabeling with 131I. The labeling procedure yielded antibodies with specific activity varying between 60 and 73 MBq/mg(More)
Three monoclonal antibodies and their Fab and Fab'2 fragments with specificity against human placental alkaline phosphatase (PLAP) were evaluated for tumour immunolocalization of human PLAP-producing Hela Hep 2 tumours in nude mice. The antibodies and their fragments were labelled with 125I and injected intraperitoneally in mice with developing Hep 2(More)
We review data from our studies of the physiological role of placental alkaline phosphatase (PLAP) and report that, in addition to functioning in catalysis, PLAP has the capacity to bind the Fc portion of human IgG. The dissociation constant for the interaction (3.86 mumol/L) indicates that the PLAP-IgG complex probably occurs in vivo. Furthermore, the(More)
OBJECTIVE The objective of this study was to quantitatively determine an immunoglobulin G receptor, placental alkaline phosphatase, and its ligand immunoglobulin G in maternal and fetal blood and to study the transport capacity of the receptor. STUDY DESIGN Venous blood samples from 66 term pregnant women and cord samples from their fetuses were obtained,(More)
The radiommunotherapeutic potential of 125I-labeled monoclonal antibodies was investigated in 48 nude mice (BALB/c, nu/nu) inoculated s.c. with the HeLa Hep 2 human adenocarcinoma cell line. This isotope, 125I, which is not commonly used for therapeutic purposes caused significant decrease in tumour growth from day 10 to day 42, when coupled to monoclonal(More)