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M R Price

Publications and source records attributed to M R Price.

At least 127 records · Page 7Linked to original sources
PubMed1986

Application of a subcellular membrane-antibody binding assay for the analysis of antigen expression in human tumours.

A micro-radioisotopic antiglobulin assay has been employed to determine the binding of monoclonal antibodies to subcellular membranes adsorbed to the wells of Terasaki Microtest Plates. A panel of 15 monoclonal antibodies was tested against 22 membrane preparations isolated from normal and malignant colo-rectal, breast and lung tissues. The assay provided an objective evaluation of antibody reactivity permitting the expression of major antigens in samples from individual surgical specimens to be defined.

Antibodies, Monoclonal↗
PubMed1986

Association of the Y hapten with glycoproteins, glycolipids and carcinoembryonic antigen in colorectal carcinoma.

The expression of the Y hapten (Fuc alpha 1----2Gal beta 1----4[Fuc alpha 1----3]GlcNAc-) defined by the monoclonal antibody C14/1/46/10 (abbreviated to C14), is frequently elevated in colo-rectal tumours in comparison to adjacent, apparently normal tissues. This determinant was shown to be expressed upon glycoproteins of approximately 200 kDa, which were isolated by immunoadsorbent chromatography from detergent-solubilized subcellular membranes and cytosol from colo-rectal carcinoma. In addition, the Y hapten was expressed upon purified carcinoembryonic antigen (CEA, 180 kDa). However, monoclonal antibodies specifically reactive with CEA or cross-reactive with CEA and NCA-1 (normal cross-reacting antigen) failed to react with the C14 defined antigens of 200 kDa. Further diversity in the expression of molecules bearing the Y hapten was established following its identification in the glycolipid fraction of colo-rectal carcinoma.

Antibodies, Monoclonal↗
PubMed1986

Epitope analysis of monoclonal antibody NCRC-11 defined antigen isolated from human ovarian and breast carcinomas.

NCRC-11 is an IgM monoclonal antibody which defines an antigen found in most epithelial malignancies. The antigen has previously been shown to be a high mol. wt. glycoprotein (greater than 400,000) and in this study, antigen preparations were isolated by immunoadsorbent chromatography from ovarian mucinous and ovarian serous cyst adenocarcinoma and from breast carcinoma. Other monoclonal antibodies, against products in normal human milk, and antibodies of the Ca series (Bramwell et al., 1985) reacted with all three antigen preparations. Tests involving epitope mapping were performed to probe the relationships of the various epitopes to that defined by the NCRC-11 antibody, and, of note, the three antigen preparations from different tumour sources were remarkably similar with respect to their relative levels of epitope expression and to their topographical distribution of epitopes. The major differences in epitope expression could be attributed to the degree of sialylation in the three antigens. The antigens from ovarian tumours expressed I(Ma) blood group determinants (defined by the antibody LICR-LON-M18) which were partially masked by sialic acid. With NCRC-11 defined antigen from breast carcinoma, this determinant was totally masked by sialic acid although neuraminidase treatment clearly exposed epitopes reactive with M18 antibodies.

Antibodies, Monoclonal↗
PubMed1986

Differentiation between monoclonal antibody-defined antigens on a human osteogenic sarcoma cell line (791T) and tumor-localizing properties of the anti-791T/36 antibody.

Two monoclonal antibodies (anti-791T/36 and anti-791T/48) prepared against an osteogenic sarcoma cell line (791T) following xenogeneic immunization, reacted against the immunizing tumor, but not against normal cells from the tumor-donor, using an indirect 125I-protein A binding assay. Both antibodies cross-reacted with a small number of other osteogenic sarcomas and a few unrelated cell lines from an extensive panel, but the specificity of these cross-reactions was different. Both antibodies were labelled with 125I to detect direct binding to target cells, and the specificity of their reactivity was essentially identical to that observed in the indirect assay. Direct binding of each labelled antibody was inhibited by pretreating target cells with its unlabelled counterpart, but the two antibodies could not inhibit each other. The binding of anti-791T/36 was also not inhibited by pretreating the target cells with sera from the 791-T-tumor donor, which were shown to contain antibody reacting with the autochthonous tumor. It is concluded that 791T has two distinct tumor-associated antigens recognized by the monoclonal antibodies, and furthermore that at least one of these antigens is independent of those recognized by the patient from which the tumor cell line was derived. The efficacy of anti-791T/36 antibody labelled with radioactive iodine was demonstrated for localizing tumor deposits growing in immunodeprived mice.

Animals↗
PubMed1985

Multiple epitopes on a human breast-carcinoma-associated antigen.

The monoclonal antibody (MAb) NCRC-11 identifies an epitope expressed variably in human breast cancer. The degree of expression of this epitope in primary operable tumours is closely related to the subsequent clinical course of the disease (Ellis et al., 1985). The target antigen for NCRC-11 was isolated from subcellular membranes of breast carcinomas and purified by immunoadsorbent chromatography. NCRC-11 epitopes were expressed upon a large glycoprotein of more than 400 kd. This material was susceptible to degradation by pronase and papain and contained N-acetylglucosamine, as indicated by its binding to wheat-germ agglutinin. The NCRC-11-defined antigen expressed epitopes for the anti-human milk-fat globule membrane antibodies HMFG-1 and HMFG-2, and other antibodies against epithelial membrane antigens (EMA, LICR-LON-M8). The reactivity of these antibodies with tumour membranes was also similar, but not identical, to that of the NCRC-11 antibody. In competitive binding-inhibition assays, these antibodies partially inhibited the binding of 125I-NCRC-11 antibody to antigen, suggesting that the epitopes involved are topographically closely associated. Sandwich immunoassays demonstrated that NCRC-11 epitopes are likely to represent repeated structures of the NCRC-11 antigen. The findings presented are interpreted as indicating that the NCRC-11 antigen expresses a variety of epitopes which are associated with normal differentiation and malignant change.

Animals↗
PubMed1984

The expression of glycoproteins on single blood platelets from healthy individuals and from patients with congenital bleeding disorders.

Glycoproteins present on the surface of blood platelets are fundamental to normal blood platelet behaviour. We have used monoclonal antibodies and flow cytofluorimetry to study the expression of glycoproteins on single platelets from normal subjects, and from patients with Glanzmann's thrombasthenia and the Bernard-Soulier syndrome. We show that normal platelets are heterogeneous in that individual cells display markedly different numbers of glycoprotein IIb/IIIa complex and glycoprotein Ib molecules. We also show that the two congenital bleeding disorders are associated with markedly reduced numbers of glycoprotein IIb/IIIa complex or glycoprotein Ib molecules on all the platelets rather than the difference residing in a sub-population.

Blood Platelets↗
PubMed1984

Analysis of a human osteogenic sarcoma antigen and its expression on various human tumour cell lines.

The murine monoclonal antibody 791T/36 cross-reacts with cells other than the immunizing osteogenic sarcoma cell line 791T, upon which the 791T/36-defined epitope is expressed on a protein of apparent molecular weight 72,000. An investigation was performed to determine whether the epitope occurred on similar molecules on other cell lines. Radiolabelled immunoprecipitates, prepared with the 791T/36 antibody, from three osteogenic sarcoma cell lines (2 OS, 788T and 278T), the prostate carcinoma EB33 and the colon carcinoma HcLo each contained a protein with a molecular weight of 72,000 as the major constituent, together with, in some cases, material of lower molecular weight. This heterogeneity was shown by neuraminidase treatment of the immune precipitates to be due to variations in sialic acid content of the antigens since, in five of the six cell lines tested, such treatment produced homogeneous material of apparent molecular weight 55,000. Chymotrypsin treatment of the immune precipitates produced in each instance a major polypeptide of molecular weight 47,000 which displayed no microheterogeneity. Immunoadsorbent-purified antigen from 791T cells was shown to bind strongly to Sepharose-wheat-germ agglutinin and less to Sepharose-concanavalin A, confirming the glycoprotein nature of this antigen. These studies demonstrate that molecules expressing the 791T/36-defined epitopes on different tumour cell lines are glycoproteins which display heterogeneity with respect to apparent molecular weight that is attributable to varying degrees of sialylation. No apparent differences were detected in the polypeptide "backbone" of these antigenic molecules.

Antigens, Neoplasm↗
PubMed1984

Preparation of four daunomycin-monoclonal antibody 791T/36 conjugates with anti-tumour activity.

As an approach to developing more specific anti-tumour therapeutic agents, daunomycin has been covalently linked to the human tumour localizing, murine monoclonal antibody 791T/36. Four procedures for coupling drug to antibody were investigated. The sugar amino group of daunomycin was modified by reaction with succinic anhydride or cis aconitic anhydride and these derivatives were linked to antibody, a carbodiimide reagent being used to produce stable peptide bonding. Alternatively, 14-bromo daunomycin was linked directly to antibody or antibody containing free thiol groups introduced by means of the heterobifunctional reagent SPDP [N-succinimidyl-3 (2-pyridyldithio) propionate] thus producing a thioether linkage. Each of the conjugates, with drug-antibody ratios of 3 to 4:1, retained a proportion of drug activity although the succinic anhydride derivative was the least cytotoxic. The three other conjugates specifically bound to tumour cells expressing the 791T/36 antibody defined antigen. In short-term assays in which tumour cells were briefly exposed to conjugates and then washed to remove non-bound conjugate, it was determined that the conjugate with the cis aconityl linkage displayed the greatest selective cytotoxicity against tumour cells reactive with the 791T/36 antibody. These studies illustrate the feasibility of preparing chemically defined drug-antibody conjugates retaining cytotoxicity and selectivity of action against tumour cells.

Animals↗
PubMed1984

Characteristics of the cell surface antigen, p72, associated with a variety of human tumours and mitogen-stimulated T-lymphoblasts.

The monoclonal antibody 791T /36, prepared against a human osteogenic sarcoma cell line, 791T , reacts with a variety of human tumours and also mitogen-stimulated PBMN cells. The target antigen as expressed upon 791T cells is a monomeric plasma membrane-associated glycoprotein with an apparent Mr of 72000. By quantitative flow cytofluorimetry, approx. 10(5) antibody molecules bound per cell to T-lymphoblasts induced with PHA or Con A, whereas only a few thousand antibody molecules bound per cell to unstimulated cells, so that the antigen may be classified as a lymphocyte activation antigen. On lymphoblasts, the 791T /36 again reacted with a protein with an apparent Mr of 72000. This antigen therefore has a dual role as a tumour marker and lymphocyte activation antigen which may be implicated in the regulation of cell proliferation.

Antibodies, Monoclonal↗
PubMed1983

Characteristics of a cell surface antigen defined by an anti-human osteogenic sarcoma monoclonal antibody.

The expression of a cell surface antigen defined by an anti-human osteogenic sarcoma monoclonal antibody was analysed by flow cytofluorometry using fluorescein-labelled antibody. Quantitative absorption tests established that the antigen was associated with plasma membranes, whereas cytosol, cellular lipids and nuclei were largely devoid of activity. Single-phase aqueous butanol solutions at non-cytolytic concentrations failed to solubilize the antigen, although treatment of cells with papain virtually abolished antigenic activity. The antigen was shown to be solubilized by the non-ionic detergent Nonidet P-40, and following lactoperoxidase-catalysed radioiodination of viable cells, extraction with detergent, immunoprecipitation of antigen with monoclonal antibody and Sepharose-Protein A, the molecular weight of antigen was determined by sodium dodecyl sulphate-polyacrylamide gel electrophoresis. The findings indicate that this human osteogenic sarcoma antigen is a monomeric integral membrane protein with an apparent molecular weight of 72,000, which is predominantly expressed at the external face of the tumour cell plasma membrane.

Antibodies, Monoclonal↗
PubMed1983

Effects of culture density on the kinetics of germ tube formation in Candida albicans.

The relationship between culture density or phase of growth at 24.5 degrees C and the ability of Candida albicans to form germ tubes when shifted to 37 degrees C was investigated. Evidence is presented demonstrating germ tube production from liquid synthetic medium cultures at all phases of growth. Previous studies reported that only cells from stationary phase cultures were competent to form germ tubes. Comparisons between exponential and stationary phase cultures indicate more rapid and more synchronous germ tube production from cells growing in the exponential phase.

Candida albicans↗
PubMed1983

Identification of an anti-human osteogenic sarcoma monoclonal-antibody-defined antigen on mitogen-stimulated peripheral blood mononuclear cells.

An anti-human osteogenic sarcoma monoclonal antibody (mouse IgG2b) termed 791T/36 was found to exert complement-dependent cytotoxicity against phytohaemagglutinin (PHA)-stimulated peripheral blood mononuclear (PBMN) cells. This reaction was examined by flow cytofluorimetry using indirect membrane immunofluorescence to detect cell-bound antibody and by measurement of the binding of fluorescein-isothiocyanate-conjugated 791T/36 antibody to cells. The antibody reacted strongly with peripheral blood blast cells induced by PHA, and there was negligible reactivity with resting lymphocytes. Maximum binding was observed after 3 days' culture with PHA, coinciding with maximum DNA synthesis, and this represented of the order of 2 X 10(5) antibody molecules bound per cell. After cell surface radioiodination of PHA-stimulated PBMN cells, detergent lysis and immunoprecipitation of antigen with 791T/36 antibody and Sepharose-protein A, the apparent molecular weight of this antigen was determined to be 72,000 by sodium dodecyl sulphate-polyacrylamide gel electrophoresis. This is identical to that of the 791T/36-defined antigen expressed on various osteogenic sarcoma cell lines [3, 17], and by this criterion the antigen is distinguishable from other cell surface markers of activated human lymphocytes.

Animals↗
PubMed1982

Cellular interactions modulating host resistance to tumours.

Active specific immunotherapy of carcinogen-induced rat tumours can be effected using vaccines containing tumour cells admixed with bacterial vaccines such as BCG and C. parvum. The nature of the tumour antigen preparation is important, the most effective immunogen being viable tumour cells whose growth is controlled by responses generated by the bacterial agent in the vaccine. Soluble tumour antigen preparations are usually ineffective due to the preferential induction of suppressor lymphocyte responses in normal hosts. In comparison, removal of suppressor precursors by cyclophosphamide treatment of animals leads to the development of tumour immunity following immunization with soluble antigen preparations. One component of the immune rejection response involves the generation of non-specific effector cells. This type of response can also be induced by administering chemical hypersensitizing agents so as to localize tumour deposits. This approach has proved highly effective in treating the guinea pig line 10 hepatoma by intralesional injection of alkylcatechols. These compounds are highly potent hypersensitizers, being the active constituents of the poison ivy/oak (urushiol oil), and localize in tumour cell membranes.

Adjuvants, Immunologic↗