Carbohydrate sequences detected by murine monoclonal antibodies

Glycosphingolipid expression in human skeletal and heart muscle assessed by immunostaining thin-layer chromatography

In this study the comparative TLC immunostaining investigation of neutral GSLs and gangliosides from human skeletal and heart muscle is described. A panel of specific polyclonal and monoclonal antibodies as well as the GM1-specific choleragenoid were used for the overlay assays, combined with preceding neuraminidase treatment of gangliosides on TLC plates. This approach proved homologies but also quantitative and qualitative differences in the expression of ganglio-, globo- and neolacto-series neutral GSLs and gangliosides in these two types of striated muscle tissue within the same species. The main neutral GSL in skeletal muscle was LacCer, followed by GbOse3Cer, GbOse4Cer, nLcOse4Cer and monohexosylceramide, whereas in heart muscle GbOse3Cer and GbOse4Cer were the predominant neutral GSLs beside small quantities of LacCer, nLcOse4Cer and monohexosylceramide. No ganglio-series neutral GSLs and no Forssman GSL were found in either muscle tissue. GM3(Neu5Ac) was the major ganglioside, comprising almost 70% in skeletal and about 50% in cardiac muscle total gangliosides. GM2 was found in skeletal muscle only, while GD3 and GM1b-type gangliosides (GM1b and GD1 alpha) were undetectable in both tissues. GM1a-core gangliosides (GM1, GD1a, GD1b and GT1b) showed somewhat quantitative differences in each muscle; lactosamine-containing IV3Neu5Ac-nLcOse4Cer was detected in both specimens. Neutral GSLs were identified in TLC runs corresponding to e.g. 0.1 g muscle wet weight (GbOse3Cer, GbOse4Cer), and gangliosides GM3 and GM2 were elucidated in runs which corresponded to 0.2 g muscle tissue. Only 0.02 g and 0.004 g wet weight aliquots were necessary for unequivocal identification of neolacto-type and GM1-core gangliosides, respectively. Muscle is known for the lowest GSL concentration from all vertebrate tissues studied so far. Using the overlay technique, reliable GSL composition could be revealed, even from small muscle probes on a sub-orcinol and sub-resorcinol detection level.

High-resolution thin-layer chromatography of gangliosides

In this review an updated overview of current improvements on thin-layer chromatography (TLC) of gangliosides over the past decade is provided. Basic general techniques and special advice is given for successful separation of glycosphingolipids. New approaches concerning continuous and multiple development, and several preparative TLC methods are also included. Emphasis is placed on TLC immunostaining and related techniques, i.e. practical applications of carbohydrate-specific antibodies, toxins and bacteria, viruses, lectins and eukaryotic cells. Thus, this review on ganglioside TLC summarizes its power as an analytical tool for a wide range of purposes.

Assay of alpha 1,3 N-acetyl-D-galactosaminyl transferase by affinity chromatography

A high-performance liquid affinity chromatography column that contains immobilized anti-A monoclonal antibody specifically retards blood group A-active oligosaccharides and can be used to detect the product(s) of the reaction catalyzed by alpha-1,3-N-acetyl-D-galactosaminyltransferase: [formula: see text] After a brief incubation (15 min) of an assay mixture containing 1-100 microliters human serum, the sugar nucleotide donor UDP-GalNAc, and radiolabeled oligosaccharide acceptors 2'-fucosyllactose and/or lacto-N-fucpentaose I blood group A-active products are isolated and quantitated in a single affinity chromatographic step that takes less than 30 min. Kinetic studies to determine the pH optima for serum alpha-3-GalNAc transferase from individuals of blood groups A1 and A2 and the Km value for UDP-GalNAc for the A1 transferase agree with previous determinations. As monoclonal antibodies against many different complex carbohydrate antigens are now available, the method described could be adapted to give rapid, inexpensive assays for a variety of glycosyltransferases.

Gangliosides: the relevance of current research to neurosurgery

Gangliosides are complex glycolipids found on the outer surface of most cell membranes: they are particularly concentrated in tissues of the nervous system. Gangliosides form part of the immunological identity of mammalian cells and are involved in a variety of cell-surface phenomena such as cell-substrate binding and receptor functions. In tumorous tissue, the ganglioside composition is altered, sometimes in direct proportion to the degree of malignancy. The literature on the glycosphingolipid composition and immunology of intracranial tumors is reviewed. Some gangliosides induce neuritogenesis and exhibit a trophic effect on nerve cells grown in vitro. In vivo, a particular ganglioside, GM1, reduces cerebral edema and accelerates recovery from injury (traumatic and ischemic) to the peripheral and central nervous systems of laboratory animals. Preliminary clinical studies have shown that treatment with gangliosides may have corresponding effects on lesions of the human peripheral nervous system. Gangliosides have not been tested in human subjects with brain injury.

Biological and NMR markers for cancer

The search for a universal tumor marker continues. Present markers range from tumor products (polyamines, glycoproteins, peptides, hormones or carbohydrate-linked markers) to reaction products produced by the host tissues during tumor invasion. Techniques used to identify them include the classical methods of histology and cytochemistry as well as the more recent radioimmunoassay and metabolic probes. The in vivo techniques of increasing use for patient monitoring are MRS (magnetic resonance spectroscopy) and MRI (magnetic resonance imaging). The efficiency of some markers and statistical methods used in analyzing data are discussed, as are the ethical problems surrounding the use of new testing methods. Recent developments in MRI and MRS, marker elucidation, and evidence for a new autocrine differentiation-inhibiting factor (ADIF) are reviewed. Future needs and approaches focus on greater utilization of indicators of the preneoplastic state and of risk to cancer, as well as more careful attention to statistical analysis.

Why are proteins O-glycosylated?

The O-linked oligosaccharides of glycoproteins are usually clustered within heavily glycosylated regions of the peptide chain. Steric interactions between carbohydrate and peptide within these clusters induce the peptide core to adopt a stiff and extended conformation and this conformational effect appears to represent a major function of O-glycosylation.

Sialyllacto-N-fucopentaose II (sialylated Le(a)) coupled to humanserum albumin used as standard in immunoassays of tumour associated antigens CA 19-9 and CA-50 in serum

Penta and hexasaccharides from human milk, containing sialic acid and/or fucose residues were conjugated to human serum albumin and used as antigens in three different methods for CA 19-9, two methods for CA-50 and one method for CA-195. In accordance with reported results, the 19-9, CC 3C 195 and C-50 monoclonal antibodies were found to react with the sialyllacto-N-fucopentaose II conjugate, although to a different extent. A negligible reaction was observed with the isomeric conjugate, sialyllacto-N-fucopentaose III, and no reaction was seen with the sialyllacto-N-tetraose conjugate. The use of defined oligosaccharide conjugates for the standardization of assays of tumour markers in serum is discussed.

Carbohydrate analysis of glycoproteins. A review

Many of the products prepared by biotechnological approaches, including recombinant genetic engineering, cell tissue culture, and monoclonal technologies, are glycoproteins. As little as five years ago, glycosylation was believed to play no significant role in the function of glycoproteins. Recent large scale testing of glycoprotein-based pharmaceuticals has indicated that both the extent and type of glycosylation can play a central role in glycoprotein activity. Although methods for compositional and sequence analysis of proteins and nucleic acids are generally available, similar methods have yet to be developed for carbohydrate oligomers and polymers. This review focuses on new, developing methods for the analysis and sequencing of the carbohydrate portion of glycoproteins. Included are: (1) the release of oligosaccharides and hydrolysis of carbohydrate chains using enzymatic and chemical methods; (2) fractionation by LPLC, electrophoresis, HPLC, and lectin affinity chromatography; (3) detection through the preparation of derivatives or by new electrochemical methods; (4) analysis by spectroscopic methods, including MS and high-field NMR; and (5) their sequencing through the use of multiple, well-integrated techniques. The ultimate goal of the analytical approaches discussed is to firmly establish structure and, thus, permit the study of structure-function relationships and eventually to allow the intelligent application of carbohydrate remodeling techniques in the preparation of new glycoproteins.

Novel methods to determine the epitopes on the asparagine-linked oligosaccharides of glycoproteins

Oligosaccharides obtained from glycoproteins by hydrazinolysis followed by N-acetylation were covalently coupled to an amino-bonded thin-layer plate or to a poly-L-lysine coating on the microtiter plate. Bound oligosaccharides can be directly detected by immunostaining or by enzyme-linked immunosorbent assay (ELISA) using a mouse monoclonal antibody. These methods are simple and require small amounts of oligosaccharides and antibodies. The methods were successfully applied to determine the epitope of F48-60, a monoclonal antibody which reacts with the N-linked sugar chains of nonspecific cross-reacting antigen 2, but not with those of carcinoembryonic antigen. The results revealed that the antibody recognizes the Gal beta 1----3GlcNAc beta 1----group.

Three novel oligosaccharides with the sialyl-Lea structure in human milk: isolation by immunoaffinity chromatography

We have determined the structures of three novel oligosaccharides isolated from human milk using the monoclonal antibody MSW 113. These oligosaccharides were purified by affinity chromatography on a column of the immobilized monoclonal antibody and by high-performance liquid chromatography. From the results of 500-MHz 1H NMR spectroscopy and fast atom bombardment-mass spectrometry, their structures were deduced to be (formula; see text) These oligosaccharides bound to MSW 113 to nearly the same extent as sialyl-Lea hexasaccharide but bound to another sialyl-Lea structure-directed monoclonal antibody, NS 19-9, only weakly.

Purification and immunochemical characterization of ascitic fluid glycoproteins containing certain tumor-associated and blood group antigen markers

Ascitic fluids from patients with various types of cancer were screened for the CA 19-9 and CA 125 tumor-associated antigenic activities. Two fluids exhibiting the highest activities were tested for their binding to various lectin-Sepharose columns resulting in both being bound best to wheat germ agglutinin (WGA) Sepharose. The WGA column eluate of one fluid was further chromatographed by HPLC and three peaks were obtained with approximate molecular weights of 3.65 MDa, 664 kDa and 330 kDa, of which only the largest fraction contained the CA 19-9 activity. The fluids were also fractionated on a Sephacryl S-400 column with most of the activity being present in or near the void volume. Monoclonal antibodies were used to demonstrate that the purified glycoproteins also contained the blood group A determinant, the four Lewis determinants Le(a), Le(b), Le(x) and Le(y), and the sialylated-Le(x) determinant, while other antibody analyses failed to detect other blood group and/or carbohydrate sequence determinants. Some of the blood group expressions could be separated from the CA 19-9 and CA 125 active glycoproteins by adsorption with various lectins other than the WGA.

Detection and isolation of oligosaccharides with Lea and Leb blood group activities by affinity chromatography using monoclonal antibodies

Affinity columns prepared by immobilizing monoclonal antibodies that specifically recognize the Lea or the Leb blood group antigens can be used for analytical or preparative isolation of oligosaccharides with the corresponding reactivities. The number of immobilized functional antibody combining sites on a column and the dissociation constants for standard oligosaccharides are determined by frontal analysis. By employing a simple approximation [K.-I. Kasai et al. (1986) J. Chromatogr. 376, 33-47] these parameters can be used to rationally design columns with properties appropriate for zonal affinity chromatography. The affinity for binding of the Lea-active oligosaccharide lacto-N-fucopentaose II (LNF II) by the anti-Lea antibody CO-514 doubles for each 8 degrees C downward shift in temperature between 37 and 4 degrees C. By zonal chromatography, Lea- or Leb-active oligosaccharides are recovered from a complex mixture of milk oligosaccharides containing more than a 20-fold molar excess of structurally similar but antigenically distinct oligosaccharides. The capacity for preparative isolation of an oligosaccharide increases in a linear fashion with the amount of antibody loaded on the solid support. The monoclonal antibodies used in these studies are products of hybridomas derived from mice immunized with human colorectal carcinoma cell lines [M. Blaszczyk et al. (1984) Arch. Biochem. Biophys. 233, 161-168]. The experiments establish that affinity chromatography applied to mixtures of oligosaccharides released by enzymatic or chemical cleavage of glycoconjugates may simplify the task of isolating and characterizing biologically interesting target antigens of monoclonal antibodies.

Detection of GD3 ganglioside in childhood acute lymphoblastic leukemia with monoclonal antibody to GD3: restriction to immunophenotypically defined T-cell disease

We have recently reported that the disialoganglioside GD3 is found in cellular lipid extracts of T-cell acute lymphoblastic malignancies (T-ALL) but is not detectable by resorcinol staining in extracts of non-T acute lymphoblastic leukemia blasts (non-T-ALL). We have now extended this study to assess the detectability of GD3 in T-ALL vs non-T-ALL utilizing an anti-GD3 antibody, R24. Gangliosides isolated from T-ALL and non-T-ALL blasts by two different methods were separated by thin-layer chromatography and stained with anti-GD3 and a control antibody specific for GM3 and sialosylparagloboside (SPG). Anti-GD3 reactivity was observed in extracts from T-ALL cells in all cases, whereas GD3 was not detected in any of the non-T-ALL samples. The anti-GM3/SPG antibody stained GM3 in all of the leukemic samples analyzed as well as SPG in the non-T-ALL samples. Indirect immunofluorescence was used to assess the expression of GD3 at the surface of leukemic blasts. Fluorescence-activated cell sorting analysis with R24 showed that whereas T-ALL blasts were highly reactive with this antibody, non-T-ALL blasts were totally unreactive. In an analysis of a larger number of leukemia patients by fluorescence microscopy, 20 out of 28 samples with the T-ALL phenotype were positive for R24, whereas zero out of 11 non-T-ALL samples were reactive. These results confirm our earlier finding of the specificity of GD3 to the T-ALL subclass of childhood leukemias and furthermore suggest the potential value of anti-GD3 as an immunological tool for the diagnosis and therapy of T-cell ALL.