Recognition of galactosylgloboside by monoclonal antibodies derived from patients with primary lung cancer

Lymph node lymphocytes from patients with primary lung cancer were immortalized with Epstein-Barr virus, and culture supernatants were screened for cell-surface reactivity against allogeneic cancer cell lines. The percentage of wells containing detectable antibodies in initial screening ranged from 1 to 17%, but the vast majority of the cultures lost antibody activity on subsequent expansion. Two antibody-secreting clones, J309 and D579, derived from separate individuals and reactive with anaplastic lung cancer cell lines, were successfully expanded and fused with the NS-1 mouse myeloma cell line. The antibodies produced by these clones exhibited identical restricted serologic reactivity against cultured cell lines and detected a carbohydrate antigen present in the neutral glycolipid fraction of MCF-7 breast cancer cells. Serologic, immunochemical, and chemical analyses revealed that the antigen recognized by antibodies J309 and D579 is galactosylgloboside [Gal(beta 1----3)GalNAc(beta 1----3)Gal(alpha 1----4)Gal(beta 1----4)- GlcCer]. Conclusions regarding the significance of these findings with respect to the biology of lung cancer await further information concerning the distribution of galactosylgloboside in normal and malignant tissues and the frequency of antibodies to this structure in normal and tumor-bearing individuals.

Neuronal precursor cells in chick dorsal root ganglia: differentiation and survival in vitro

Neuronal precursor cells present in dorsal root ganglia (DRG) during early development have been previously shown to differentiate in vitro to neurons, as characterized by morphology, cell surface antigens, and electrophysiological properties (H. Rohrer, S. Henke-Fahle, T. El-Sharkawy, H. D. Lux, and H. Thoenen, 1985, Embo J. 4, 1709-1714). In the present study the conditions necessary for the initial differentiation and long-term survival of these cells were established, and the neurotransmitter phenotype of the newly differentiated neurons was analyzed. Neuronal precursor cells isolated from chick DRG at Embryonic Day 6 (E6) were found to require the presence of a polyornithine substrate coated with either laminin or fibronectin for initial neurite production and long-term survival. Neurons were unable to develop on polyornithine alone or on polyornithine coated with BSA. The survival and neurite outgrowth from neuronal precursor cells was not affected by the presence of nerve growth factor (NGF) during the first 9 hr in culture. NGF also had no effect on the proportion of cells expressing the neuron-specific Q211 antigen. However, after this initial differentiation period the neurons did require the presence of a survival factor. The neurons could be maintained for at least 6 days in culture both in the presence of NGF and in the presence of brain-derived neurotrophic factor (BDNF). At saturating concentrations of both survival factors no additive effects could be observed, indicating a complete overlap of NGF- and BDNF-responsiveness. Although the same proportion of cells survived with either NGF or BDNF during the first 3 days in culture, survival decreased in the presence of BDNF but not in the presence of NGF during the following 3 days in culture. The loss of BDNF responsiveness in vitro was also observed in vivo. After 6 days in culture about 70% of the neurons expressed substance P immunoreactivity, and approximately the same proportion was positive for myelin-associated glycoprotein immunoreactivity. The neurons did not express properties of adrenergic neurons such as tyrosine hydroxylase immunoreactivity or norepinephrine uptake. These findings indicate that the neuronal precursor cells from E6 DRG acquire the same characteristics in vitro as in their normal in vivo environment.

Purification of Forssman and human blood group A glycolipids by affinity chromatography on immobilized Helix pomatia lectin

A method for the affinity purification of intact glycolipids having nonreducing terminal alpha 1-3 linked N-acetylgalatosamine residues has been developed. This technique relies on the retention of the carbohydrate-binding specificity of immobilized Helix pomatia lectin in aqueous solutions of tetrahydrofuran. Both Forssman glycolipid and a mouse blood group A-active hexaosylceramide were bound by columns of the lectin equilibrated in a solvent containing 95% tetrahydrofuran and 5% water. After application of a step gradient of increasing water content up to 50%, the specifically bound glycolipids were eluted in solvent containing N-acetylgalactosamine. The Forssman and A-active glycolipids were similarly purified in a single chromatographic step from total lipid extracts of sheep and human type A erythrocyte stroma, respectively. Nonspecifically bound lipids and glycolipids were eluted from this column by simply increasing the water content of the eluting buffer. The extension of this method to other carbohydrate-binding proteins including lectins and monoclonal antibodies may provide a rapid purification of glycolipids based on their carbohydrate structures.

Detection of patients with cancer by monoclonal antibody directed to lactoneotetraosylceramide (paragloboside)

A hybridoma producing monoclonal antibody (H11) directed to lactoneotetraosylceramide (paragloboside) has been established from spleen cells of a mouse immunized with paragloboside. The monoclonal antibody H11 (immunoglobulin M type) was selected from five clones showing different reactivities with paragloboside. The monoclonal antibody was highly specific to paragloboside and lacked reactivity with other glycolipids including glucosylceramide, lactosylceramide, globotriaosylceramide, globotetraosylceramide, gangliotriaosylceramide, gangliotetraosylceramide, and GalNAc beta 1-4[NeuAc alpha 2-3]Gal beta 1-4Glc beta 1-1Cer. However, the monoclonal antibody (H11) was found to bind to lactosamine-containing glycolipids at their terminals, such as i- and I-type glycolipids as well as paragloboside. A two-step sandwich radioimmunoassay method for paragloboside antigen in serum was established by using the monoclonal antibody. The mean paragloboside antigen concentration in the sera from 20 normal individuals was 25.3 ng/ml. If the cutoff value was set at 80.9 ng/ml [25.3 + 2 x 27.8 (SD)], only 1 of 20 healthy controls had an elevated paragloboside value in the serum, whereas sera from 9 of 12 (75.0%) hepatoma, 4 of 10 (40%) pancreatic cancer, 16 of 40 (40.0%) stomach cancer, and 6 of 10 (60%) lung cancer patients had elevated paragloboside values. Sera from 3 of 8 hepatitis patients and 7 of 10 liver cirrhosis patients were estimated to be positive but sera from 16 patients with benign disease had paragloboside levels lower than the cutoff value. A larger amount of the antigen was found in liver metastases from colorectal carcinoma compared to the normal counterpart. The antigen was also detected in the medium of various human cancer cells and meconium. However, the antigen in the sera, medium, meconium, and cancer tissue seemed to be associated with glycoprotein or lipoprotein, because most of the antigen activity was eluted in the void volume fraction on high-performance liquid chromatography with a gel filtration column.

Glycosphingolipids in sheep liver, kidney, and various blood cells

Sheep liver, kidney, bone marrow, and erythrocytes gave their own specific patterns of neutral and acidic glycosphingolipids. A major neutral glycosphingolipid was found to be lactosylceramide in the liver and bone marrow, glucosylceramide in the kidney, and Forssman glycolipid in the erythrocytes, respectively. The Forssman glycolipid was not found in the liver, kidney, bone marrow, leukocytes, platelets and plasma even by a sensitive thin layer chromatography immunostaining, but two unknown glycosphingolipids, reactive to Forssman antibody, were slightly recognized in addition to Forssman glycolipid in the erythrocytes. Sulfolipids were found certainly in the kidney, but not found in the other tissues and cells. GM3 as a major ganglioside and other minor gangliosides whose sialic acids consisted of both N-acetylneuraminic acid and N-glycolylneuraminic acid were found in liver, kidney, leukocytes, platelets, and plasma, whereas the sheep erythrocytes were found to contain three major gangliosides of GM3, disialosyltetraglycosylceramide (probably disialosyllactoneotetraosylceramide) and disialosylhexaglycosylceramide (probably disialosyllacto-norhexaosylceramide) which had N-glycolylneuraminic acid and N-acetyl-neuraminic acid.

Polarity of the Forssman glycolipid in MDCK epithelial cells

To determine whether epithelial plasma membrane glycolipids are polarized in a manner analogous to membrane proteins, MDCK cells grown on permeable filters were analyzed for the expression of Forssman ceramide pentasaccharide, the major neutral glycolipid in these cells. In contrast to a recent report which described exclusive apical localization of the Forssman glycolipid (Hansson, G.C., Simons, K. and Van Meer, G. (1986) EMBO J. 5, 483-489), immunofluorescence and immunoelectron microscopic staining revealed the Forssman glycolipid on both the apical and basolateral surfaces of polarized cells. Immunoblots indicated that the Forssman antigen was detectable only on glycolipids and not on proteins. Analysis of metabolically labeled glycolipids released into the apical and basal culture medium, either as shed membrane vesicles or in budding viruses, also demonstrated the presence of the Forssman glycolipid on both apical and basolateral membranes of polarized cells. Quantitation of the released glycolipid indicated that the Forssman glycolipid was concentrated in the apical membrane. These results are consistent with previous reports which described quantitative enrichment of glycolipids in the apical domain of several epithelia.

Characterization of human sperm plasma membrane: glycolipids and polypeptides

The plasma membranes from ejaculated human spermatozoa were removed by nitrogen cavitation (600 PSI for 10 min) and isolated by centrifugation followed by a discontinuous sucrose density gradient centrifugation. Glycolipid analysis of the plasma membrane revealed a three-fold enrichment in gangliosides: GM3 and GD1a/GD1b and neutral glycolipids: globoside and sulfatide as compared to that of whole human sperm. Two dimensional electrophoresis of human sperm plasma membranes revealed about 75 polypeptides. Several of these polypeptides were similar in migration and in display of shape and color to that found in boar sperm plasma membranes.

Sialosyllactotetraosylceramide, 3'-isoLM1, a ganglioside of the lactotetraose series isolated from normal human infant brain

A ganglioside antigen was detected in infant human brains by the monoclonal antibody C-50. Structural analysis of the isolated ganglioside antigen showed it to be 3'-isoLM1, sialosyllactotetraosylceramide. The concentration of this ganglioside in human infant brain was 0.5 nmol/g.

Forssman glycolipid, an antigenic marker for a major subpopulation of macrophages from murine spleen and peripheral lymph nodes

Three hybridoma clones were isolated after hybridization of a mouse myeloma line with splenocytes from rats immunized with Forssman glycosphingolipid (Fo). Two of these clones produced Fo-specific monoclonal antibodies (MAB) of the IgM class, one MAB of the IgG2c class. In complement-dependent depletion experiments and immunofluorescence studies on the nature of Fo-positive leukocytes in CBA/J mice the following results were obtained: whereas blood monocytes, polymorphonuclear leukocytes, and lymphocytes were Fo negative, 5 to 10% of suspended spleen cells were positive. The majority of these were macrophage-like, glass- and nylon-adherent, nonspecific esterase-positive phagocytizing cells carrying Ia and globoside markers. These cells participated as accessory cells in the mixed lymphocyte culture reaction. In cell suspensions from axillary and inguinal lymph nodes, 2% were Fo positive. They were enriched up to 70% in the glass-adherent, esterase-positive population from this source. In contrast, no Fo-positive cells were detected in mesenteric lymph nodes, and less than 0.1% of the resident peritoneal macrophages bore this marker. The percentage of Fo-positive cells increased to 1% in thioglycollate-elicited peritoneal cells. Immunostaining of cryosections of lung and liver tissue showed alveolar macrophages and Kupffer cells, respectively, to be Fo negative.

Characterization of neutral glycosphingolipids from fetal human brain: evidence for stage-specific expression of the globo, ganglio, and neolacto series in the central nervous system

Neutral glycosphingolipids were isolated from normal human fetal brains, at 22 to 23 weeks gestation. They were identified as monohexosylceramides, lactosylceramide, and glycolipids belonging to the globo (globotriaosylceramide) and ganglio (gangliotriaosylceramide) series. In addition, considerable amounts of neolactotetraosylceramide and III3-alpha-fucosyl-neolactotetraosylceramide were detected. Although neutral glycolipids of the globo, ganglio, and neolacto series have been demonstrated in the brains of cases with some sphingolipidoses, they are not present in appreciable amounts in differentiated normal brain. Therefore, the present and previous observations would imply that the metabolism of these glycolipid series actively occurs in the normal brain at an early stage of differentiation and continues thereafter in the brain in the case of some sphingolipidoses. The diseased brain is most probably accompanied by a disturbance of differentiation.

Analysis of NMR spectra of sugar chains of glycolipids by multiple relayed COSY and 2D homonuclear Hartman-Hahn spectroscopy

We applied multiple relayed COSY and 2D homonuclear Hartman-Hahn spectroscopy to globoside, a glycolipid purified from human red blood cells. The subspectra corresponding to individual sugar components were extracted even from overlapping proton resonances by taking the cross sections of 2D spectra parallel to the F2 axis at anomeric proton resonances, so that unambiguous assignments of sugar proton resonances were accomplished.

An antigen present in rat adenocarcinoma and normal colon non-epithelial stroma is a novel Forssman-like glycolipid based on isoglobotetraosylceramide

A glycolipid with blood group A activity detected in the non-epithelial stroma of normal rat colon but not in epithelial cells (Hansson, G.C., Karlsson, K.-A., and Thurin, J. (1984) Biochim. Biophys. Acta 792, 281-292), was purified to homogeneity from normal rat colon and rat colon adenocarcinoma. Mass spectrometry and 1H-NMR spectroscopy of the intact permethylated derivative and gas chromatography after degradation revealed the structure GalNAc alpha 1----3GAINAc beta 1----3Gal alpha 1----3Gal beta 1----4Glc beta 1----1Cer, with the predominant ceramide containing sphingosine and non-hydroxylated 24:0 fatty acid. This identifies this glycolipid as a novel Forssman-like glycolipid, which is a tumor-associated antigen by definition, since it is not present in the normal rat large intestinal epithelium cells but in rat adenocarcinoma derived from these cells.

Characterization of new gangliosides of the lactotetraose series in murine xenografts of a human glioma cell line

The major mono- and disialogangliosides of the extensively characterized established human glioma line D54MG were isolated and purified from subcutaneous solid xenografts grown in athymic (nu/nu) mice. Structural determination showed that they belonged to the lactotetraosylceramide series. The sialyllactotetraosylceramide contained 90% N-glycolyl- and 10% N-acetylneuraminic acid linked in an alpha 2-3 linkage (IV3NeuGc-LcOse4Cer, IV3NeuAc-LcOse4Cer). The disialogangliosides had a previously undescribed type of structure with sialic acids linked to the terminal galactose in an alpha 2-3 linkage and to N-acetylglucosamine in an alpha 2-6 linkage. Not only did species with NeuAc or NeuGc occur, but also species with mixtures of the two sialic acids, e.g. NeuAc and NeuGc. The schematic structures of the new disialogangliosides are (Formula:see text).

A murine monoclonal IgM antibody specific for blood group P antigen (globoside)

A murine monoclonal IgM erythrocyte antibody appeared to have anti-P (anti-globoside) specificity. The antibody was a relatively weak cold agglutinin, but a strong haemolysin and its reactivity with red cells was markedly enhanced by enzyme treatment. This antibody was used to study the cell and tissue distribution of globoside. Globoside was not only detectable on red cells and erythroblasts, but also on endothelial cells and on subsets of platelets, megakaryocytes and fibroblasts. It was not detectable on granulocytes, monocytes and most peripheral blood lymphocytes. Neither was it present on erythroblast precursors (CFU-E, BFU-E), pro-erythroblasts or on the cells of the pro-erythroblastic cell lines K562 and HEL. However, K562 cells expressed globoside when induced to mature into erythroblasts by sodium butyrate. Cells of patients with various leukaemias were also tested. A significant number of positively reacting cells was frequently (six out of 18) seen in cases with a CML blast crisis (CML-BC) and rarely in AML (four out of 37 cases). In CML-BC the P-positive cells were probably erythroblasts and/or megakaryoblasts. Thus, globoside appeared to be an interesting marker in CML-BC of the erythroblastic or mixed erythroblastic-megakaryoblastic type.

Globoseries glycosphingolipids of human meconium

Globoside and an extended globoseries glycosphingolipid with a blood group H determinant were isolated from pooled human meconia and structurally characterized by mass spectrometry, proton NMR spectroscopy, and degradational techniques using GC and GC-MS analyses. Both species contained mainly phytosphingosine and hydroxy fatty acids characteristic for human intestinal epithelial cells. With the same techniques also minor amounts of globoside with sphingosine and nonhydroxy fatty acids and a novel globoseries tetraglycosyl ceramide with a terminal N-acetylglucosamine were isolated and structurally characterized.

Complete structural analysis of globoseries glycolipids by two-dimensional nuclear magnetic resonance

Combined two-dimensional proton nuclear magnetic resonance allowed the determination of complete oligosaccharide structures of glycolipids belonging to the globo series, without any other analytical methods. Although a chemical modification by peracetylation was required for the above purpose, the derivatization permitted facile assignment of the pyranose ring proton resonances of the oligosaccharide moiety. Two-dimensional chemical-shift-correlated spectroscopy of the acetylated glycolipid enabled us to elucidate the glycosidic positions from the chemical shifts of the protons at the substituted sites. The monosaccharide species were also identified from the characteristic splitting patterns of the methine protons on individual pyranose rings. The sequence of the monosaccharides was inferred from the interresidue connectivity across glycosidic linkages shown by two-dimensional nuclear Overhauser effect spectroscopy, which also gave intraresidue interaction on the pyranose rings. The linkage sites of long oligosaccharide chains having more than five monosaccharides, such as globopentaosylceramide, were analyzed by two-dimensional J-relayed coherence transfer, which yielded 1,3 interactions along with 1,2 interactions.

[Analysis of glycosphingolipids from human myeloid leukemias]

Neutral glycosphingolipids of human myeloid leukemia cells in different differentiation stages from nine patients were analyzed by high performance liquid chromatography. All cells contained ceramide monohexoside, lactosylceramide and neutral glycosphingolipids of the lacto-series. However, some of the leukemic cells contained neutral glycosphingolipids of the globo-series. Especially myelomonocytic cells (French-American-British or FAB classification M4) and poorly differentiated cells (FAB M0 and M1) were found to contain globo glycosphingolipids. On myeloblast cells, (FAB M2), globo glycosphingolipids were missing or present only in very low amounts. It seemed, therefore, that on myeloid leukemic cells the glycosphingolipid composition may be dependent on their differentiation stage.

Immunological analysis of glycolipids on cell surfaces of cultured human tumor cell lines: expression of lactoneotetraosylceramide on tumor cell surfaces

Glycolipids of human cell lines of colonic adenocarcinoma (Colo 205 and BM 314), gastric tumor (AZ 521 and KATO-III), and lung tumor (A 549) were studied by the immunohistochemical fluorescence technique, flow cytometric analysis and immunostaining on thin layer chromatoplates with antibodies against gangliotriaosylceramide (Gg3Cer), gangliotetraosylceramide (Gg4Cer), fucogangliotetraosylceramide (Fuc-Gg4Cer), blood group B active lipid, globopentaosylceramide (Gb5Cer) and lactoneotetraosylceramide (nLc4Cer). Anti-nLc4Cer antibody was the only antibody which reacted with all the tumor cell lines used. The glycolipid fractions of each cell line separated by Iatrobeads column chromatography were immunostained with the six antibodies mentioned above on thin layer plates. The presence of nLc4Cer was detected in all cell lines. On the other hand, Gg4Cer was detected in gastric tumor cell lines, and Gg3Cer was detected in AZ 521. Based on these results, the tumor cell lines were analyzed by flow cytometry using anti-nLc4Cer antibody. About 70% of total cells in each cell line were separated as nLc4Cer-expressing cells. The present findings, together with the occurrence of nLc4Cer in ascitic fluids of cancer patients (Taki, T., Kojima, S., Seto, H., Yamada, H., & Matsumoto, M. (1984) J. Biochem. 96, 1257-1265), suggest that nLc4Cer may be a tumor-associated lipid.

Identification of a novel ganglioside on erythrocytes with blood group Cad specificity

The blood group Cad antigen is a carbohydrate structure well characterized on the sialoglycoproteins of the red cell membrane from some rare individuals (Blanchard, D., Cartron, J. P., Fournet, B., Montreuil, J., Van Halbeck, H., and Vliegenthart, J.F.G. (1983) J. Biol. Chem. 258, 7691-7695). However, protease treatment of whole cells did not destroy their antigenic activity which indicated that glycolipid might also be involved in the antigenic reaction. A crude ganglioside fraction was prepared from Cad cells and found to inhibit the hemagglutination reaction, whereas neutral glycolipids were inactive. Further analysis of the ganglioside extract from Cad erythrocytes by thin layer chromatography revealed an unusual profile characterized by a lower content of sialosylparagloboside and the presence of a novel ganglioside of slower mobility. Immunochemical studies demonstrate that this ganglioside binds Helix pomatia lectin and inhibits human anti-Sda antibody. In addition, a ganglioside with identical chromatographic mobility can be obtained by the enzymatic transfer of GalNAc from UDP-GalNAc to sialosylparagloboside using a microsomal preparation from human kidney. These results together with cell surface labeling experiments suggest that the major ganglioside of Cad erythrocytes might be derived from sialosylparagloboside by substitution with an additional N-acetylgalactosamine residue.

[Study on a tumor associated antigen on a rat fibrosarcoma cell line--chemical structure of an antigen reactive to a rat natural antibody]

Conventionally bred rats possess a natural antibody (NA) in their sera, which is cytotoxic in its effect on a KMT-17 tumor cell line derived from a fibrosarcoma induced by 3-methylcholanthrene and can be absorbed by normal rat tissues. We have succeeded in isolating and purifying an antigen reactive to NA from the tumor cells as a glycosphingolipid (GSL). GSLs from the tumor cells were separated into neutral and acidic fractions. The former fraction was judged to be antigenic as detected by its capacity to absorb NA. The antigenic fraction was further separated into 7 fractions, Fr.A to Fr.G, by silicic acid chromatography. The antigenic activity was detected in only Frs.D and E, although Fr.D was a more potent antigen than Fr.E. Chemical and immunochemical analyses showed that both the fractions are lactoneotetraosylceramide (paragloboside), Gal (beta 1-4) GlcNAc (beta 1-3) Gal (beta 1-4) Glc (beta 1-1) ceramide, and that the more active GSL, Fr.D, contains larger amounts of long fatty acid chains. Inhibition studies using disaccharides and monosaccharides indicated that a N-acetyllactosamine moiety, Gal (beta 1-4) GlcNAc, is a specific site of the GSL antigen to NA. These results suggest that a sugar chain portion of this GSL is required for defining specificity and that the ceramide portion plays a role in potentiating the antigenicity of this GSL antigen.

Chromogenic labeling of monosaccharides using 4'-N,N-dimethylamino-4-aminoazobenzene

Twenty-three monosaccharides, e.g., D- or L-pentoses, D- or L-hexoses, heptose, 2- or 6-deoxyhexoses, 2-deoxy-2-aminohexoses, hexuronic acids, and N-acetylmuramic acid, were coupled to the azo dye 4'-N,N-dimethylamino-4-aminoazobenzene by reductive amination using sodium cyanoborohydride as reducing agent and in the presence of pentaerythritol. The structure of the colored glycamines was established by mass spectrometry. The average yield of the reaction was more than 80%. The sugar derivatives were separated either by silica-gel thin-layer chromatography or by high-performance liquid chromatography. Spectrophotometric quantitation was performed in the visible range at the picomole level. The method was applied to the determination of the sugar composition of the glycosphingolipid globotetraosyl ceramide and the human milk oligosaccharide lacto-N-fucopentaose I.

Enzymatic and organizational difference in expression of a Burkitt lymphoma-associated antigen (globotriaosylceramide) in Burkitt lymphoma and lymphoblastoid cell lines

In our previous study, a Burkitt lymphoma-associated antigen defined by a monoclonal antibody, designated 38.13, was characterized as globotriaosylceramide (Gb3, Gal alpha 1----4 Gal beta 1----4 Glc beta 1----1 Cer) (Nudelman, E., Kannagi, R., Hakomori, S., Parsons, M., Lipinski, M., Wiels, J., Fellous, M., and Tursz, T. (1983) Science (Wash. D.C.) 220, 509-511). Consequently, we have studied the enzymatic basis and organization of Gb3 expression in Burkitt as compared with non-Burkitt lymphoblastoid cell lines. Burkitt lymphoma cell lines (Ramos, Daudi, Put) were characterized by a high chemical quantity of Gb3, high enzyme activity for synthesis of Gb3 (UDP-Gal:LacCer alpha-galactosyltransferase), and a high degree of surface exposure of Gb3, as determined by galactose oxidase/NaB[3H]4 and by cytofluorometry with the monoclonal antibody to Gb3 (38.13). Non-Burkitt lymphoblastoid cell lines (Priess, Remb1, and ARH77) were characterized by the absence of Gb3 at the cell surface detected by cytofluorometry or cell-surface labeling. The cell lines Priess and Remb1 did not contain Gb3 and showed a low alpha-galactosyltransferase activity for Gb3 synthesis. However, the cell line ARH77, though it did not express Gb3 at the cell surface, was found to contain a large chemical quantity of Gb3 and a high level of alpha-galactosyltransferase activity for Gb3 synthesis. However, Gb3 of ARH77 cells was exposed by sialidase treatment, but not by protease treatment, although Gb3 itself was not sialylated. The crypticity of Gb3 in ARH77 cells could be associated with an adjacent sialosyl residue of a second glycoconjugate at the cell surface, in the same way as Gg3 in mouse lymphoma L5178 (Urdal, D. L., and Hakomori, S. (1983) J. Biol. Chem. 258, 6869-6874). Thus, the expression in Burkitt and non-Burkitt lymphoma is dependent on (i) Gb3 synthesis due to alpha-galactosyltransferase activity and (ii) membrane organization of Gb3, which may be controlled through interaction with the sialosyl residue of a second glycoconjugate.

Structural characterization of glycosphingolipids by direct chemical ionization mass spectrometry

This report describes the use of direct chemical ionization mass spectrometry with ammonia as the reagent gas (NH3-DCI) for structure analysis of underivatized, permethylated and permethylated and reduced glycosphingolipids. In contrast to ionization by electron impact, the NH3-DCI mass spectra exhibit intense molecular and carbohydrate sequence-related ions using microgram amounts of sample. Underivatized glycosphingolipids with up to two sugar residues yield abundant protonated and ammonia-cationized molecular ions and structurally significant fragments. Permethylation in conjunction with NH3-DCI can be used to obtain molecular weight as well as oligosaccharide sequence and branching information on neutral, acidic and complex-type glycosphingolipids with up to five sugar residues. Reduction of the permethylated derivatives gives rise to several new, structurally significant fragments in the corresponding NH3-DCI mass spectra which enable fatty acid and base compositions to be determined. Isotopically labeled reagent gases have been used to confirm the assignment of fragment structures and to demonstrate that the ions observed are unique to the NH3-DCI mass spectra.

Blood group H antigen with globo-series structure. Isolation and characterization from human blood group O erythrocytes

Blood group H antigen with globo-series structure, reacting with the monoclonal antibody MBrl, was isolated and characterized from human blood group O erythrocytes. The structure was identified by methylation analysis, direct probe mass spectrometry, and 1H-nuclear magnetic resonance spectroscopy as shown below: Fuc alpha 1----2Gal beta 1----3GalNAc beta 1----3Gal alpha 1----4Glc beta 1----1Cer.

The glycosphingolipid globoside as a serological marker on cytolytic T lymphocyte precursors and alloantigen-responsive proliferating T lymphocytes in murine spleen

Biochemical analyses of murine lymphocytes have shown that the glycosphingolipid globoside (Glo) is present exclusively on alloantigen-stimulated murine T lymphocytes (Gruner, K. R., Van Eijk, R. V. W. and Mühlradt, P. F., Biochemistry 1981. 20: 4518). An anti-Glo antibody has now been raised in rabbits immunized with purified antigen. Most activity was recovered in the IgM fraction. The specificity of the antibody was ascertained in an enzyme-linked immunosorbent assay with purified glycosphingolipids bound to the solid phase. In antibody-dependent complement lysis experiments the anti-Glo eliminated about 20% of nylon wool-nonadherent splenic T cells of CBA/J mice. To determine the functional identity of these Glo+ cells, the effects of Glo+ cell elimination on mitogen stimulation with concanavalin A and lipopolysaccharide, as well as the effects on the mixed lymphocyte culture (MLC) reaction and cell-mediated lympholysis with mitomycin-treated DBA/2 splenocytes as stimulator cells were studied. Whereas lipopolysaccharide stimulation was not affected by elimination of Glo+ cells, there was a slight inhibitory effect on the concanavalin A stimulation, and a severe inhibition of the MLC reaction and the generation of H-2d-specific cytolytic T lymphocytes. Addition of interleukin 2 increased the MLC reaction, but interleukin 2-saturated cultures were also severely inhibited by anti-Glo and complement treatment. Combined treatment with anti-Glo and anti-Lyt-1 or anti-Lyt-2 antibodies, and determination of cytolytic T lymphocyte precursor frequencies in limiting dilution cultures after Glo+ cell elimination showed that a large proportion of T cells proliferating in a primary MLC are Lyt-1+,2+,3+Glo+, whereas in secondary MLC they are Lyt-1+,2-,3-,Glo+. Fifty % of the cytolytic T lymphocyte precursors in primary as well as secondary MLC are Glo+. The Glo marker is lost upon differentiation to cytolytic T lymphocyte effector cells. It is discussed herein that Glo is a marker for alloantigen-stimulated precursor T lymphocytes of both helper and cytolytic T cells.