Biomedical subjects

V E Dube

Publications and source records attributed to V E Dube.

At least 19 recordsLinked to original sources

PubMed1988

Suppression of lymphocyte function with breast carcinoma I-active glycopeptides.

Patients with metastatic breast carcinoma (BCa) have defective peripheral blood lymphocyte (PBL) responsiveness to mitogenic and antigenic stimulation. In the following experiments, glycopeptides were isolated from the pronase digests of breast carcinoma tissue. After elution from Sephadex G-50, glycopeptides from BCa inhibited PBL responsiveness to mitogenic (PHA) stimulation. The glycopeptides contained blood group I-antigenic determinants. These experiments demonstrate the presence of blood group I-active peptides in breast carcinoma that suppress peripheral blood lymphocyte functions. Further studies are in progress.

Blood Group Antigens↗

PubMed1987

The structural relationship of blood group-related oligosaccharides in human carcinoma to biological function: a perspective.

Blood group-related oligosaccharides have been isolated from a limited number of carcinomas. The carcinoma-associated oligosaccharides show chain elongation, for example due to repeating Gal 1,4 GlcNAc 1,3 sequences, or a higher degree of branching, which permit increased sialylation and fucosylation. Abnormal carbohydrate structures have been demonstrated on tumor cell membranes by immunological techniques, which suggests deletion of ABH, accumulation of 'crypt' antigens such as I and T antigens, and abnormal expression of Lewis antigens. Changes in carcinoma-associated oligosaccharides can result from altered biosynthetic processing in the Golgi apparatus or the occurrence of abnormal tumor glycosyltransferase isoenzymes. Structural alterations of oligosaccharides on the tumor cell membrane are related to the regulation of tumor growth, cell-cell interaction, cell differentiation, and metastasis. Glycoproteins secreted by tumor cells into the circulation evoke cellular and humoral immunity and cause immune suppression by binding to cytotoxic T lymphocytes and lymphocyte subsets. The relationship of oligosaccharide structures to biologic function awaits elucidation.

Animals↗

PubMed1987

An immunosorbent assay for blood group I antigens in breast carcinoma.

Tumor cells elaborate and release into the circulation a variety of glycoproteins. An enzyme-linked immunosorbent assay (ELISA) was developed to monitor carbohydrate structures secreted into the circulation. Among these antigens are the structures specific for the blood group I antigens, which are incompletely converted to ABH antigens on the membranes of tumor cells. The I antigens in the sera of 67 women with breast carcinoma (BCa), 58 with benign breast disease (BBD), and 47 controls were measured by the ELISA. In this assay, I antigen from ovarian cyst mucin was bound to the wells of polystyrene microtiter plates. The monoclonal human anti-I antibody (Hy) was added to the wells along with perchloric acid extracts of patient and control sera at five different dilutions. The anti-I binding to the solid-phase I antigen was determined after incubation steps with peroxidase-labeled anti-human IgM and substrate. The amount of sera extracts giving 50% inhibition of anti-I (Hy) binding was determined from the inhibition curves which were corrected by integrating the slope values into that of the standard curve obtained with extracts of normal sera. The I antigens were significantly higher in pathologic stage (PS) IV sera (P less than 0.001), and comparable in PS I, PS II, and PS III and BBD sera to those in control sera. The anti-I (Hy) binds strongly Gal 1,4 GlcNAc 1,6 Gal (alpha GalNAc); Gal 1,4 GlcNAc 1,6 (Gal 1,4 GlcNAc 1,3) Gal; and to a lesser extent Gal 1,4 GlcNAc 1,3 Gal 1,4 GlcNAc (0.06, 0.09, and 0.35 mM, giving 50% inhibition, respectively). It was concluded that similar or related structures may be expressed on the membrane of metastatic BCa cells.

Antibodies, Neoplasm↗

PubMed1986

Characterization of the oligosaccharide alditols from ovarian cyst mucin glycoproteins of blood group A using high pressure liquid chromatography (HPLC) and high field 1H NMR spectroscopy.

A combination of reverse phase and normal phase high pressure liquid chromatography has been used to separate the reduced oligosaccharides produced by alkaline borohydride degradation of a blood group A ovarian cyst mucin glycoproteins. Fourteen compounds, ranging in size from a monosaccharide to a decasaccharide, have been isolated preparatively using a Zorbax C-18 reverse phase column eluted with water and a MicroPak AX-5 normal phase column eluted with aqueous acetonitrile. The purity of the products and their structures were determined from the fully assigned high field proton NMR spectra. The resonances of exchangeable amide protons, observed by the Redfield selective pulse sequence in H2O, were assigned by decoupling to the resonances of H2 of the 2-acetamido sugars. Nuclear Overhauser effects were used to establish the relationship of the anomeric protons and those of the aglycone. In exception to earlier proposals that nuclear Overhauser effect on irradiation of the anomeric proton should always be observed at the proton attached to the aglycone carbon, we find that for the linkage of GalNAcp(1----3)Gal, nuclear Overhauser effect on irradiation of the alpha-anomeric proton resonance is observed not at H3 but at H4 of galactose. A combination of NMR methods and enzymatic degradation was employed to determine the structures of 13 different oligosaccharides of which seven have not previously been reported. These oligosaccharides, which terminate with beta-Gal, alpha-Fuc, beta-GlcNAc, and alpha-GalNAc, account for 75% of the total glycoprotein carbohydrate, the remainder being isolated as a mixture of glycopeptides and a high molecular weight polysaccharide whose NMR spectrum implies a simple repeating subunit structure closely related to that of the oligosaccharides.

Adenocarcinoma, Mucinous↗

PubMed1986

Specificity of the monoclonal anti-I antibody (Hy).

In previous work we found that a monoclonal cold hemagglutinin from patient Hy strongly bound antigens contained in stage IV breast cancer sera. To infer the chemical structure of the antigens expressed in the cancer sera, we studied the specificity of the antibody (Hy). The antibody (Hy) had I specificity, based on agglutination scores with adult and cord red blood cells. The binding of the antibody to synthetic and milk oligosaccharides was determined using a solid phase enzyme immunoassay (EIA). The anti-I antibody (Hy) strongly bound LacNAc0-Me, LacNAc1----6Gal, LacNAc1----6 (LacNAc1----3)Gal, LacNAc-1----6 alpha GalNAc, LacNAc1----3LacNAc, and LacNAc, 0.05, 0.06, 0.09, 0.22, 0.35 and 0.75 mM giving 50% inhibition, respectively. The anti-I antibody (Hy), similar to the anti-I antibody (Ma), strongly bound LacNAc1----6Gal, but it differed from the anti-I antibody (Ma) in its cross-reactivity with the i sequence. The anti-I antibody (Hy) showed similar reactivities as the hybridoma monoclonal antibodies M18 and M39 with LacNAc1----6Gal and with the i-active sequence. The EIA procedure is a useful alternative to either radioimmunoassay or immunoprecipitation method in the study of anti-I,i specificities.

Antibodies, Monoclonal↗

PubMed1986

Human embryonic liver cell differentiation. I. Changes in specific mRNA synthesis correlates with parameters signaling oncologic alterations.

When incubated in preconditioned medium, i.e. spent media from the hepatocellular carcinoma (PLC/PRF/5) cell cultures, human embryonic liver (HEL) cells differentiate and acquire oncologic phenotypes. This is caused by transcriptional alterations in fetal gene expression. This occurs when hepatocytes are proliferating rapidly and secreting alpha fetoprotein (AFP), and later when the quiescent state is reached with secretion of albumin (ALB). The present studies examined the parameters signaling oncologic transformation during liver cell differentiation in the conditioned medium. mRNAs coding for AFP, ALB and HBsAg were isolated from HEL, adult liver cells (ADLC) and from PLC/PRF/5 cells, respectively. cDNA molecules complementary to these polysomal mRNA molecules were constructed and labeled with 32P. These tracers were used to quantitate changes in cellular mRNA X AFP, mRNA X ALB and mRNA X HBsAg directly by DNA molecular hybridization during HEL cells cultivation in the preconditioned medium. Under these conditions, the changes in cellular mRNA X HBsAg and mRNA X AFP correlated with an increased tumorigenicity in athymic Nu/Nu mice, membrane galactosyltransferase and phospho-tyrosine kinase activities.

Albumins↗

PubMed1985

Characterization of lacto-N-hexaose and two fucosylated derivatives from human milk by high-performance liquid chromatography and proton NMR spectroscopy.

The branched hexasaccharide whose trivial name is lacto-N-hexaose (LNH) as well as a mono- and a difuco-derivative were isolated from human breast milk of a Lewis a positive donor by high-performance liquid chromatography (HPLC). Reversed-phase HPLC on C18 columns which have been used previously in our laboratory for successful separations of the smaller milk oligosaccharides were not effective in this system. However, normal-phase HPLC on an amino-bonded silica column (Varian AX-5) gave both analytical and preparative separations. The identity of the LNH core structure was verified both by HPLC and by NMR spectroscopy of the fucosidase digestion products of the fucosylated oligosaccharides. LNH was identified by NMR spectroscopy of the reduced and acetylated derivative whose high field spectrum has been previously reported. The positions of fucosylation of beta-GlcNAc residues were determined by the characteristic chemical shifts of the resonances assigned to alpha-fucose H1 and H5. The assignment of many of the resonances to sugar ring protons was possible using difference decoupling methods. The observation of nuclear Overhauser effects between the anomeric protons and the aglycone protons of adjacent residues confirmed the assignment of the glycosidic linkages.

Chromatography, High Pressure Liquid↗

PubMed1978

Variation of cold agglutinin levels.

Cold agglutinin levels were determined in 120 individuals ranging in age from 1 to 64 years using untreated and ficin-treated group O erythrocytes. The geometric mean titer for untreated cells was 5.7 +/- 1.1 SEM and for ficin-treated cells 18.7 +/- 1.1 SEM. The mean titers and scores for various blood groups were not significantly different. Titers and scores correlated significantly to total serum IgM concentration (p less than 0.001). Females had significantly higher cold agglutinin levels than males (p less than 0.001). A significant decrease of cold agglutinins occurred in the 26- to 64-year age group as compared to the 11- to 25-year age group (p less than 0.01). The data should contribute to a clearer understanding of the biological impact of cold agglutinins.

Adolescent↗

PubMed1977

Caprylate-dependent auto-anti-e.

A caprylate-dependent autoantibody with specificity for the e antigen of red cells is described. The antibody was completely inactivated by 2-mercaptoethanol and was probably of the IgM immunoglobulin class. The antibody had no apparent specificity for albumin. Reactivity of the described antibody may depend upon conformational change of red cell Rh antigen by caprylate.

Adult↗

PubMed1975

Hemolytic anemia caused by auto anti-N.

The second case of hemolytic anemia caused by auto anti-N, occurring in a 7-year-old boy, is described. The antibody was IgG, as shown by the use of specific anti-human IgG Coombs sera, failure of inactivation by 2-mercaptoethanol, and chromatographic separation on a G-200 Sephadex column.

Anemia, Hemolytic, Autoimmune↗

PubMed1974