PubMed Health⌕ Search

Biomedical subjects

H Durbin

Publications and source records attributed to H Durbin.

At least 19 recordsLinked to original sources
PubMed1997

Genomic and cDNA sequence analysis of the cell matrix adhesion regulator gene.

The cell matrix adhesion regulator (CMAR) gene has been suggested to be a signal transduction molecule influencing cell adhesion to collagen and, through this, possibly involved in tumor suppression. The originally reported CMAR cDNA was 464 bp long with a tyrosine phosphorylation site at the extreme 3' end, which mutagenesis studies had shown to be central to the function of this gene. Since the discovery of a 4-bp insertion polymorphism within the originally reported coding region, further sequence information has been obtained. The cDNA has been extended 5' by approximately 2 kb revealing a 559-bp region showing strong homology to the proposed 5' untranslated sequence of a murine protein kinase receptor family member, variant in kinase (vik). CMAR genomic sequencing has shown the presence of an intron, the intron/exon boundary lying within this region of homology. An RNA transcript for CMAR of approximately 2.5 kb has also been identified. The data suggest complex mechanisms for control of expression of two closely associated genes, CMAR and the vik- associated sequence.

ATPases Associated with Diverse Cellular Activitie↗
PubMed1994

An epitope on carcinoembryonic antigen defined by the clinically relevant antibody PR1A3.

The monoclonal antibody PR1A3 has been used successfully for in vivo imaging of colorectal cancers, and several properties associated with this antibody, including minimal reactions of the antibody with circulating antigen in patients' sera, differentiate it from anti-carcinoembryonic antigen (CEA) antibodies used in similar studies. However, the antigen bound by PR1A3 was identified as CEA by analysis of somatic cell hybrids and by antigen expression from yeast artificial chromosomes, cosmids, and cDNA clones. The molecular weight, presence of a glycosyl-phosphatidylinositol anchor, elevation of surface expression by gamma-interferon, and N-terminal amino acid sequence all confirmed the antigen identification as CEA. A series of biliary glycoprotein-CEA hybrid proteins was produced which demonstrated that the epitope bound by the antibody was at the site of membrane attachment and involved parts of the glycosyl-phosphatidylinositol anchor and the B3 domain of CEA to form a conformational epitope. Access to this epitope, although possible when the antigen was on the cell surface, appeared to be blocked when CEA was released from the cell. The nature and location of the epitope on CEA are proposed to be responsible for the unique properties of the antibody.

Animals↗
PubMed1993

Adhesion to carcinoembryonic antigen by human colorectal carcinoma cells involves at least two epitopes.

Carcinoembryonic antigen (CEA) may be involved in both cell-cell and cell-substrate adhesion. Our purpose was to determine whether epitopes involved in the homophilic binding of human colorectal carcinoma cells to CEA participated in adhesion to basement membrane proteins. Three human colorectal adenocarcinoma cell lines and one CHO cell line transfected with CEA cDNA were tested in a solid-phase adhesion assay. The 2 CEA-expressing carcinoma cell lines (KM-12c and CCL 188) and the transfectant, but not the parental CHO line, bound to CEA. The CEA-non-producing carcinoma line (Clone A) did not bind to CEA. All colorectal carcinoma cell lines, the transfectant and the parental CHO line bound to laminin, while the colorectal carcinoma lines bound to type-IV collagen. MAbs to epitopes on CEA that cross-react with non-specific cross-reacting antigen (NCA) inhibited adhesion of CEA-expressing cells to CEA. MAbs to non-cross-reactive epitopes of CEA did not block adhesion to CEA. When the inhibitory anti-CEA antibodies were compared in a competitive radioimmunoassay, 2 distinct epitopes were identified. Epitope I is in the N-terminal domain and defined by MAbs MN3, T84.1 and C110, whereas epitope II is located in the repeating loop domains and is recognized by antibodies MN15, PR3B10 and NP1. None of the antibodies to epitope I or II blocked adhesion by KM-12c or CCL 188 cells to laminin or type-IV collagen. Thus, at least 2 different regions on CEA participate in adhesion to CEA but not to collagen or laminin by CEA-expressing human colorectal carcinoma cells.

Adenocarcinoma↗
PubMed1990

Further characterization, isolation and identification of the epithelial cell-surface antigen defined by monoclonal antibody AUA1.

The human epithelial antigen recognized monoclonal antibody (MAb) AUA1 has been characterized as a cell-surface glycoprotein. It has been isolated from human colonic mucosa by AUA1 affinity separation. N-terminal peptide sequence of this purified material has revealed a 17 amino acid sequence which identifies it with one of a group of similar epithelial/tumor-associated glycoproteins defined by a variety of MAbs. Using the polymerase chain reaction to map the gene encoding this antigen, our previous AUA1 antigen assignment to chromosome 2 has been confirmed.

Antibodies, Monoclonal↗
PubMed1990

Carcinoembryonic antigen functions as an accessory adhesion molecule mediating colon epithelial cell-collagen interactions.

We have previously shown that a human colon carcinoma cell line (SW1222) expresses a collagen receptor recognizing the Arg-Gly-Asp tripeptide sequence found in collagen. This receptor mediates the cellular attachment to collagen and, subsequently, the glandular differentiation seen in a three-dimensional collagen gel culture. In a search to identify cell surface molecules mediating the adhesion and differentiation of SW1222 cells, we have screened a panel of monoclonal antibodies recognizing epithelial cell surface determinants for their ability to inhibit the collagen binding of SW1222 cells. We have found that four monoclonal antibodies recognizing the 180-kDa carcinoembryonic antigen (CEA) glycoprotein and other members of the CEA family inhibited (up to 87%) the binding of SW1222 cells to type I collagen matrix. Using a cell attachment assay, we have not detected any direct collagen binding of either purified CEA or another CEA-expressing human colon carcinoma cell line (LS174T). These data suggest that CEA is not a collagen-binding protein itself but is likely to be associated with the functional Arg-Gly-Asp collagen receptor expressed by SW1222 cells. We suggest that CEA may function as an accessory molecule, controlling the functional activity of the SW1222 collagen receptor.

Amino Acid Sequence↗
PubMed1988

Production of monoclonal antibodies to placental alkaline phosphatase: preliminary characterisation includes identification of one antibody reactive with routinely fixed histological preparations.

We describe the production and preliminary characterisation of a set of monoclonal antibodies (MAbs) raised against placental alkaline phosphatase (PLAP). Different forms of antigen presentation, PLAP or PLAP-like expressing whole cells, placental membranes or purified PLAP were used to immunise BALB/c mice. Initial screening was carried out against the immunising material by ELISA, against fresh frozen placental sections by immunostaining and against purified PLAP using an enzyme capture assay. The most successful fusions were those following whole cell immunisation, producing 27 antibodies that all reacted with both the placental and testicular form of enzyme. These all showed a broadly similar pattern of reactivity when tested against a range of human malignant cell lines. Further characterisation identified one antibody, 8B6, as strongly reactive with formalin-fixed paraffin-embedded placental sections. This antibody also performed well when tested against a range of normal and malignant routinely fixed tissue sections. Of 14 antibodies analysed for immunoglobulin isotype, 10 were of the IgGI subclass. In competitive binding studies with 7 antibodies to discriminate epitopes, at least 4 distinct binding sites were identified. By Scatchard analysis on 4 of these antibodies, binding constants of 3 were within the range 3.5-5.3 x 10(-9)M. Unusually the 4th antibody appeared to recognise 2 separate antigen sites with binding constants of 2.1 and 7.5 x 10(-9)M. In a preliminary study to compare patterns of reactivity of a selection of the new antibodies with a limited number of sera from smokers and seminoma patients, results indicate their potential for further typing within the placental group of enzymes.

Alkaline Phosphatase↗
PubMed1988

Monoclonal antibodies to placental alkaline phosphatase: preclinical evaluation in a human xenograft tumour model of F(ab')2 and Fab fragments.

Six new placental alkaline phosphatase monoclonal antibodies (MAbs) have been evaluated in order to select a potentially clinically useful antibody fragment for use in immunoscintigraphy or therapy. Initially, 3 antibodies were identified by trial pepsin digestion as likely to give satisfactory F(ab')2 yield. The corresponding intact antibodies were then compared for ability to localise human xenograft tumours in athymic mice. Of the best of these, designated 3F6, F(ab')2 and Fab fragments were then evaluated in similar xenograft experiments. In intact antibody biodistribution comparisons, 3F6 showed good tumour retention and satisfactory specific/non-specific ratios at 8 days. In similar fragment biodistribution experiments 3F6 F(ab')2 gave the highest tumour/blood ratio (10) and tumour/organ ratios (19) and the best specific/non-specific localisation. This fragment also showed higher absolute uptake in the tumour than intact antibody, 18.9% and 14.4% respectively of the injected dose. As expected, fragments showed much faster blood clearance rates than whole antibody. For Fab the in vivo instability by 6 hr was also demonstrated.

Alkaline Phosphatase↗
PubMed1987

Evidence for tumour necrosis factor/cachectin production in cancer.

Labile tumour-necrosis-factor-like (TNF) activity was detected by means of an enzyme-linked immunosorbent assay in 50% of 226 freshly obtained serum samples from cancer patients with active disease. In contrast, only 3% of 32 samples from normal subjects and 18% of 39 samples from cancer patients with no clinically evident disease were positive for this factor, with low levels of activity. Greater proportions of serum samples from patients with ovarian or oat-cell carcinoma were positive (69% and 63%) than those from patients with lymphoma (26%). RNA preparations from peripheral-blood mononuclear cells and solid tumours were probed with TNF complementary DNA; evidence of TNF messenger RNA was found in 8 of 11 samples of peripheral-blood mononuclear cells from cancer patients, but only 1 of 8 normal subjects, and in 2 of 6 colorectal tumours. As yet the inducing stimulus and the clinical significance of TNF production in cancer are not understood.

Adult↗
PubMed1987

A sensitive micro-immunoassay using beta-galactosidase/anti-beta-galactosidase complexes.

This paper describes a new sensitive microELISA based on enzyme/anti-enzyme complexes following an unlabelled antibody bridging step. beta-Galactosidase/anti-beta-galactosidase complexes were made using a monoclonal antibody raised against bacterial (E. coli) beta-galactosidase and enzyme activity was quantified with a fluorogenic substrate. Because of its high sensitivity the assay is particularly suitable for the detection of limited amounts of antigen. One application illustrated is the analysis of Class I and Class II histocompatibility antigens on peripheral blood lymphocytes using 5000 cells/well in 60-well Terasaki or 96-well microtitre plates.

Animals↗
PubMed1987

Identification of immunoreactive monoclonal antibody fragments for improved immunoscintigraphy.

Results obtained in animal models suggest that antibody fragments may have advantages over whole immunoglobulin for in vivo localisation studies. Proteolytic digestion of monoclonal antibodies may however yield a mixture of products unsuitable for in vivo use. This report describes a method whereby the immunoreactive products of antibody digestion can be identified by probing nitrocellulose blots of the gel-separated digest with the specific antigen. Optimum conditions for the production of the reactive fragments can then be determined and once identified they can be purified to homogeneity. Using this method conditions have been defined for the production of F(ab)2 and Fab fragments from a papain digest of an antibody to placental alkaline phosphatase (H17E2). In this case the antigen has enzyme activity which can be used to detect binding to the immunoreactive bands on the Western blots. In vivo experiments in nude mice carrying xenografts of a tumour expressing the H17E2 reactive antigen were performed to determine the efficacy of localisation of the purified fragments as compared to the whole antibody. As expected the absolute levels of radioactivity localised in the tumour was highest using whole antibody, whereas the F(ab)2 fragments produced the highest tumour:blood ratios.

Alkaline Phosphatase↗
PubMed1986

Characterization and chromosomal assignment of a human cell surface antigen defined by the monoclonal antibody AUAI.

We describe the chromosomal assignment and biochemical characterization of the genetic locus controlled by a human cell surface antigen which is defined by the monoclonal antibody (MAb) AUAI. This gene product is only expressed on epithelial cells. Therefore, human-mouse somatic cell hybrids of epithelial origin were used to assign this gene to chromosome 2. Cell surface iodination of the hybrids and parental cells followed by immunoprecipitation and polyacrylamide gel electrophoresis showed that AUAI detected a single 35-kDa protein. The MAb AUAI reacted on tissue sections with a subset of normal epithelial cells, but in tumours it showed a much wider distribution, though still only on epithelium-derived tumours.

Antibodies, Monoclonal↗
PubMed1986

Antibody-guided irradiation of malignant pleural and pericardial effusions.

Tumour-associated monoclonal antibodies (HMFG1, HMFG2 and AUA1) radiolabelled with iodine-131 were given intracavitary (intrapleurally and intrapericardially) to patients with malignant effusions. Ten out of 13 effusions (3 pericardial and 7 pleural) responded completely with no fluid reaccumulation between 3 and 18 months. No clinical or other toxicity was observed. This new method of treatment for recurrent malignant effusions is non-toxic and effective resulting in improved quality of life, and, in some cases, prolongation of survival.

Adult↗
PubMed1986

Limitations of radiolabeled monoclonal antibodies for localization of human neoplasms.

Tumor-associated monoclonal antibodies were radiolabeled with 125I and 131I and given i.v. in pairs to 19 patients 1-26 days prior to surgical excision of primary and metastatic breast, ovarian, and gastrointestinal tumors. For individual patients each monoclonal antibody was designated as specific or nonspecific according to prior immunoperoxidase staining results on the appropriate target neoplastic tissues. Quantitation of antibody uptake was performed on resected normal and neoplastic tissues. Although good tumor:non-tumor ratios were obtained with the specific antibodies (maximal tumor:blood ratio, 35.8:1 at 12 days postadministration), the absolute amount of radiolabel detected in tumors was small (mean value of 0.015% of total injected amount per g of tumor occurring 1 day postadministration). Furthermore, both specific and nonspecific antibodies accumulated in normal lymph nodes to a significant extent (mean value of 0.0026% of total injected amount per g of tissue occurring 1 day postadministration). Knowledge of such data is essential prior to considering therapeutic uses of radiolabeled monoclonal antibodies.

Adult↗
PubMed1985

Indium-111 labelled monoclonal antibody to placental alkaline phosphatase in in the detection of neoplasms of testis, ovary, and cervix.

A monoclonal antibody (H17E2) against placental alkaline phosphatase (PLAP) and testicular placental-like alkaline phosphatase was labelled with indium-111 and used in radioimmunoscintigraphy of 15 patients known or suspected to have germ-cell carcinoma of the testis or carcinoma of the ovary or cervix. Good images of neoplastic lesions were obtained in most patients with active disease. In 1 patient with testicular teratoma and elevated human chorionic gonadotropin who had a normal computed tomography scan, the labelled antibody located microscopic disease in a lymph node, which was then removed. No false positive localisation was seen in patients with PLAP-negative tumours or sites of inflammation. This method may be helpful in the diagnosis, staging, and monitoring of PLAP-positive neoplasms of testicular, ovarian, and cervical origin.

Adult↗
PubMed1985

Antibody guided irradiation of brain glioma by arterial infusion of radioactive monoclonal antibody against epidermal growth factor receptor and blood group A antigen.

In a patient with recurrent grade IV glioma of the brain resistant to conventional treatment an antibody guided isotopic scan showed uptake by the tumour of a monoclonal antibody (9A) that was developed against epidermal growth factor receptor but cross reacted with blood group A antigen. As a therapeutic attempt antibody labelled with 1665 MBq (45.0 mCi) iodine-131 was delivered to the tumour area by infusion into the internal carotid artery. Computed tomography showed regression of the tumour after treatment, and an appreciable and sustained clinical improvement was noted without any toxicity. Delivery of irradiation guided by monoclonal antibody delivered by arterial infusion of the tumour area may be of clinical value in the treatment of brain gliomas resistant to conventional forms of treatment.

ABO Blood-Group System↗
PubMed1985

123I radioiodinated antibody imaging of occult ovarian cancer.

A monoclonal antibody HMFG2 labeled with iodine 123 (123I) was given to a patient who had ovarian cancer. The scan taken 18 hours after administration of the antibody demonstrated the presence and the position of residual tumor in the pelvis that was not previously detected by ultrasonography and computerized tomography (CT) scanning. The presence of tumor was confirmed by surgery and histologic as well as immunoperoxidase examination of resected tissues. The tumor mass found was less than 0.8 cm in diameter. It is concluded that, in the search for residual or early ovarian cancer in the pelvis, monoclonal antibody scanning using 123I-labeled HMFG2 can complement ultrasonography and CT scanning.

Adenocarcinoma↗