A series of human erythrocyte glycosphingolipids reacting to the monoclonal antibody directed to a developmentally regulated antigen SSEA-1

A series of glycolipid antigens reacting with the monoclonal antibody directed to the stage-specific embryonic antigen 1 was isolated and characterized from group O human erythrocyte membranes. A ceramide heptasaccharide (Structure 1), ceramide nonasaccharide (Structure 2), and ceramide decasaccharide (Structure 3) have been characterized (formula, see text) The main feature of this glycolipid series is its long core sugar chain with a nonbranched repeating N-acetyllactosamine (norpolylactosamine). This characteristic is in contrast to that of co-existing H-active glycolipid series in which the longer core structures are branched type repeating N-acetyllactosamine (isopolylactosamine). The reactivity of these glycolipids to monoclonal anti-stage-specific embryonic antigen 1 antibody varied proportionately to the length of their core sugar chains. A possible significance of these glycolipids as developmentally regulated antigens and as cancer-associated antigens was discussed.     

Novel fucolipids accumulating in human adenocarcinoma. II. Selective isolation of hybridoma antibodies that differentially recognize mono-, di-, and trifucosylated type 2 chain

A series of glycolipids having the X determinant (Gal beta 1----4 [Fuc alpha----3]GlcNAc) at the terminus and a fucosyl alpha 1----3 residue at the internal GlcNAc residue have been isolated and characterized from tumor tissues (Hakomori, S., Nudelman, E., Levery, S.B., and Kannagi, R. (1984) J. Biol. Chem. 259, 4672-4680. A series of monoclonal antibodies that differentially recognize glycolipids with mono-, di-, and trifucosylated type 2 chain have been isolated and characterized. The antibody FH4 shows a remarkable preferential reactivity towards di-/or trifucosylated type 2 chain, i.e. it does not react with monofucosylated structures, including lactofucopentaosyl (III) ceramide (III3FucnLc4), monofucosyl neolactonorhexaosylceramide (y2, V3FucnLc6), and monofucosyl neolactonoroctaosylceramide (Z1, VII3FucnLc8), but reacts well with di- and trifucosylated type 2 chain structures such as difucosyl neolactonorhexaosylceramide (III3V3Fuc2nLc6) and trifucosyl neolactonoroctaosylceramide (III3V3VII3Fuc3nLc8). Two other monoclonal antibodies, FH5 and ACFH18, preferentially react with trifucosylated type 2 chain structure (III3V3VII3Fuc3nLc8), although cross-reactivity with difucosylated type 2 chain (III3V3Fuc2nLc6) was observed. They showed a minimal cross-reaction with monofucosylated type 2 chain. In contrast, the antibody FH1 does not react with III3FucnLc4 but reacts with V3FucnLc6, III3V3Fuc2nLc6, and III3V3VII3Fuc3nLc8. Two monoclonal antibodies, FH2 and FH3, do not discriminate among various glycolipids having fucosylated type 2 chain, and their reactivities are essentially similar to previously established antibodies directed to the X determinant, such as anti-SSEA-1, WGHS 29, VEP8 and 9, My-1, etc. This series of antibodies will be useful to detect the specific type of glycolipid with fucosylated type 2 chain accumulating in human cancer and in undifferentiated cells.     

Further characterization of the putative glycolipid receptor for mif: Role of fucose associated with an acidic glycolipid

Water soluble glycolipids were extracted from guinea pig macrophages. These glycolipids, when incubated with macrophages, augment the cells' response to migration inhibitory factor. The glycolipids were fractionated by diethylaminoethyl-Sephadex ion exchange chromatography into neutral and acidic fractions. Only the acidic glycolipid fraction was able to enhance the responsiveness of macrophages to migration inhibitory factor. Additional studies indicate that the enhancing activity of these glycolipid preparations can be abrogated by the removal of terminal fucose residues with α-L-fucosidase. The possibility that fucose functions as an essential component of a macrophage glycolipid receptor for migration inhibitory factor is discussed.     

Confirmation of minor components of less polar neutral and acidic glycolipids in monkey brain tissue

Crude glycolipids, prepared without alkali treatment in advance, were separated into neutral and acidic glycolipids by DEAE-Sephadex A-25 (acetate form) column chromatography. Each glycolipid was further fractionated by a Silica gel 60-column chromatography. By matrix-assisted laser desorption/ionization time-of-flight mass spectrometry with delayed ion extraction (DE MALDI-TOF MS) of the intact glycolipid fractions, the less polar neutral glycolipids were found to contain alkali-labile ester cerebrosides and Galb-1-Diradylglycerols, whereas the less polar acidic glycolipids were found to contain alkali-labile ester sulfatide, HSO(3)-3Gal-1-Diradylglycerols, and novel alkali-stable plasmalo-sulfatides and ester or plasmalo HSO(3)-3Galb-1-Diradylglycerols as minor components of glycolipids in monkey brain tissue.In conclusion, minor components of less polar neutral and acidic glycolipids in monkey brain tissue were confirmed as ester cerebrosides, Galb-1-Diradylglycerols, ester sulfatides, HSO(3)-3Galb-1-Diradylglycerols, and novel plasmalo-sulfatides and ester or plasmalo HSO(3)-3Galb-1-Diradylglycerols by DE MALDI-TOF MS.     

The monoclonal antibody directed to difucosylated type 2 chain (Fuc alpha 1 leads to 2Gal beta 1 leads to 4[Fuc alpha 1 leads to 3]GlcNAc; Y Determinant)

One of the monoclonal (AH-6) antibodies prepared by hybridoma technique against human gastric cancer cell line MKN74 was found to react with a series of glycolipids having the Y determinant (Fuc alpha 1 leads to 2Gal beta 1 leads to 4[Fuc alpha 1 leads to 3]GlcNAc). The structure of one such glycolipid isolated from human colonic cancer and from dog intestine was identified as lactodifucohexaosyl-ceramide (Fuc alpha 1 leads to 2Gal beta 1 leads to 4[Fuc alpha 1 leads to 3]GlcNAc beta 1 leads to 3Gal beta 1 leads to 4Glc beta 1 leads to 1-ceramide; IV3,III3Fuc2nLc4Cer). The hapten glycolipid did not react with monoclonal antibodies directed to Lea, Leb, and X-hapten structures, and the AH-6 antibody did not react with the X-hapten ceramide pentasaccharide (Gal beta 1 leads to 4[Fuc alpha 1 leads to 3]GlcNAc beta 1 leads to 3Gal beta 1 leads to 4Glc beta 1 leads to 1-ceramide), H1 glycolipid (Fuc alpha 1 leads to 2Gal beta 1 leads to 4GlcNAc beta 1 leads to 3Gal beta 1 leads to 4Glc beta 1 leads to 1-ceramide), nor with glycolipids having the Leb (Fuc alpha 1 leads to 2Gal beta 1 leads to 3[Fuc alpha 1 leads 4]GlcNAc beta 1 leads to R) determinant. The antibody reacted with blood group O erythrocytes, but not with A erythrocytes. Immunostaining of thin layer chromatography with the monoclonal antibody AH-6 indicated that a series of glycolipids with the Y determinant is present in tumors and in O erythrocytes.     

Carbohydrate analysis of chicken heart glycolipids

Neutral and acidic glycolipids were extracted from chicken hearts. The neutral and acidic compounds were separated by preparative thin-layer chromatography into eight and two fractions, respectively. Total hydrolysis by mineral acid, permethylation analysis, and sequential cleavage with exoglycosidases showed the presence of glycolipids that belong to the globo- and gala-oligosaccharide series, i.e., the monohexosylceramides Glc-Cer and Gal-Cer, the dihexosylceramides Gal beta 1-4Glc-Cer and Gal alpha 1-4Gal-Cer, the tetrahexosylceramides GalNAc beta 1-3Gal alpha 1-4Gal beta 1-4Glc-Cer and GalNAc alpha 1-3GalNAc beta 1-3Gal alpha 1-4Gal-Cer (III3GalNAc alpha-Ga3Cer) and four subfractions of the Forssman glycolipid GalNAc alpha 1-3GalNAc beta 1-3Gal alpha 1-4Gal beta 1-4Glc-Cer. With the notable exception of III3GalNAc alpha 1-Ga3Cer, all glycolipids with terminal GalNAc alpha 1-3GalNAc1 reacted on thin-layer chromatograms with a monoclonal anti-Forssman antibody. The major components of the acidic fraction glycolipids were characterized as the lactose-based gangliosides Glac1 (GM3) and Glac2 (GD3).     

Expression and localization of Lewisx glycolipids and GD1a ganglioside in human glioma cells

We analysed the glycolipid composition of glioma cells (N-370 FG cells), which are derived from a culture of transformed human fetal glial cells. The neutral and acidic glycolipid fractions were isolated by column chromatography on DEAE-Sephadex and analysed by high-performance thin-layer chromatography (HPTLC). The neutral glycolipid fraction contained 1.6 µg of lipid-bound glucose/galactose per mg protein and consisted of GlcCer (11.4% of total neutral glycolipids), GalCer (21.5%), LacCer (21.4%), Gb4 (21.1%), and three unknown neutral glycolipids (23%). These unknown glycolipids were characterized as Lewis^x (fucosylneolactonorpentaosyl ceramide; Le^x), difucosylneolactonorhexaosyl ceramide (dimeric Le^x), and neolactonorhexaosyl ceramide (nLc6) by an HPTLC-overlay method for glycolipids using specific mouse anti-glycolipid antibodies against glycolipid and/or liquid-secondary ion (LSI) mass spectrometry. The ganglioside fraction contained 0.6 µg of lipid-bound sialic acid per mg protein with GD1a as the predominant ganglioside species (83% of the total gangliosides) and GM3, GM2, and GM1 as minor components. Trace amounts of sialyl-Le^x and the complex type of sialyl-Le^x derivatives were also present. Immunocytochemical studies revealed that GD1a and GalCer were primarily localized on the surface of cell bodies. Interestingly, Le^x glycolipids and sialyl-Le^x were localized not only on the cell bodies but also on short cell processes. Especially, sialyl-Le^x glycolipid was located on the tip of fine cellular processes. The unique localization of the Le^x glycolipids suggests that they may be involved in cellular differentiation and initiation of cellular growth in this cell line.     

Glycolipid changes in murine myelogenous leukemias: neutral glycolipids as markers for specific populations of leukemias

We have studied the glycolipid composition of six different murine myelogenous leukemias as well as that of T-cell leukemias and normal spleen cells. Neutral and acidic lipid fractions were isolated by column chromatography on DEAE-Sephadex and analyzed by high-performance thin-layer chromatography (HPTLC) and an HPTLC overlay method. Murine myelogenous leukemias were found to contain globo- and ganglio-series neutral glycolipids, e.g., glucosylceramide (Glc-cer), lactosylceramide (Lac-cer), globotriaosylceramide (Gb3), globoside (Gb4), Forssman glycolipid (Gb5), and asialo-GM1 (GA1). Monoblastic leukemia cells contained increased proportions of Gb3, Gb4, Gb5, and GA1. Monocytic and myelomonocytic leukemia cells contained increased proportions of Glc-cer and Lac-cer. Especially, Glc-cer accounted for approximately 60% of the total neutral glycolipids in monocytic leukemia cells. Gb3 was the major neutral glycolipid in reticulum cell neoplasm type A, and it accounted for approximately 75% of the neutral glycolipids. GA1 was the major neutral glycolipid in myeloblastic and granulocytic leukemia cells as well as T-cell leukemias. Especially, granulocytic leukemia cells contained predominantly GA1, and it accounted for approximately 80% of the total neutral glycolipids. The pattern of gangliosides in myelogenous leukemias was more complex when compared with that of the neutral glycolipids; murine myelogenous leukemias contained at least 13 gangliosides, including such major gangliosides as GM1, GM1b containing N-acetyl neuraminic acid and N-glycolyl neuraminic acid, and Ga1NAc-GM1b. Alterations of glycolipid composition in murine myeloid leukemias may be associated with cellular differentiation and maturation, and therefore these characteristic glycolipid species may be regarded as markers for specific populations of leukemia cells.     

The presence of blood group A-active glycolipids in cancer tissues from blood group O patients

Glycolipids were isolated from human gastric cancer tissues and normal mucosae. Sulfogalactosylceramide, ganglioside and neutral glycolipid fractions were separated by DEAE-Sephadex and silica gel column chromatography. Sulfogalactosylceramide contents were higher in the cancer tissues than in the normal mucosae. Ganglioside contents showed considerable variations but in the cancer tissues in mole percentage of ganglioside GM3 was higher than in the normal mucosae. The cancer tissues contained more neutral glycolipids than normal tissues. Glycolipids of lacto-series, including fucolipids, were markedly increased in the cancer tissues. Blood group A-active glycolipids were found in the cancer tissues from two patients with blood group O but not found in the uninvolved tissue associated with the cancer tissue.     

Blood group A determinants with mono- and difucosyl type 1 chain in human erythrocyte membranes

Application of a monoclonal antibody defining monofucosyl type 1 chain A (AH21) revealed the presence of a glycolipid having the same thin-layer chromatography mobility as Aa but showing a clear reactivity with AH21. This glycolipid was detectable in Lea-b- erythrocytes but not in Lea+b- or Lea-b+ erythrocytes. Another monoclonal antibody defining difucosyl type 1 chain A (HH3) detected the presence of a glycolipid component reacting with this antibody in Lea-b+ erythrocytes but not in Lea+b- or Lea-b- erythrocytes. The component defined by monoclonal antibody AH21 and that defined by HH3 were isolated and characterized by 1H NMR spectrometry and methylation analysis as having the structures (Formula: see text) The 1H NMR spectra of these glycolipid antigens were characterized by resonances for anomeric protons that are identical with those of glycolipids with type 1 chain previously isolated but distinctively different from those of type 2 chain analogues. Resonances reflecting ceramide composition are characteristic for these antigens from human erythrocytes and are distinguishable from those of the same antigen from other sources.     

Novel fucolipids accumulating in human adenocarcinoma. III. A hybridoma antibody (FH6) defining a human cancer-associated difucoganglioside (VI3NeuAcV3III3Fuc2nLc6)

A new fucoganglioside, 6B, which accumulates in human colonic adenocarcinoma but is absent in normal colonic mucosa, was isolated from a monosialoganglioside fraction of colonic adenocarcinomas. The structure of this ganglioside was identified as shown below by methylation analysis, direct probe mass spectrometry, and enzymatic degradation followed by examination of the degradation products with specific monoclonal antibodies. (formula; see text) The hybridoma (FH6) secreting a monoclonal IgM antibody directed to this glycolipid was selected by reactivity of the antibody with this ganglioside and lack of reactivity with other glycolipids having a closely related structure, such as sialosyllactoneotetraosylceramide (IV3NeuAcnLc4), sialosyllactofucopentaosy(III)ceramide (IV3NeuAcIII3FucnLc4), sialosyllactofucopentaosy(II)ceramide (sialosyl-Lea glycolipid; IV3NeuAcIII4FucLc4), and 6C fucoganglioside (sialosyl 2 leads to 6 fucoganglioside; VI6NeuAcIII3FucnLc6). The antibody was highly reactive with a large variety of human cancer cells, but was less reactive or did not react with a variety of normal cells.     

Glycosphingolipids of rabbit endometrium and their changes during pregnancy.

The glycolipids of nonpregnant and pregnant rabbit endometrium were characterized using a combination of biochemical and immunochemical techniques. Quantitative analyses indicated a 70% decline in acidic glycolipid (ganglioside) content during early pregnancy (day 6), and a 2.5-fold increase in neutral glycolipid content during later pregnancy (day 26). The major gangliosides of rabbit endometrium were identified by thin-layer chromatography as GM3 and GD3, with minor amounts of GM1, GD1a and GT1b. The major neutral glycolipids were identified similarly as globo-series structures Gb3 and Gb4. Monoclonal antibodies (mAbs) directed to glycolipid antigens permitted the detection of additional glycolipid species, including sialylated, sulfated and fucosylated lacto-series structures. Difucosyl Ley structure (defined by mAb AH-6) and sulfated-galactosyl structure (defined by mAb VESP 6.2) were identified by indirect immunofluorescence along the luminal surface of the endometrium during the implantation period. Rapid changes in the glycolipid composition of endometrial cells during early pregnancy may facilitate embryo adhesion and trophectoderm outgrowth during implantation.     

Consecutive analysis of sphingoglycolipids on the basis of sugar and ceramide moieties by high performance liquid chromatography

A quantitative consecutive method was developed for analysis of sphingoglycolipids in biological materials by high performance liquid chromatography (HPLC). Crude lipid extracts were separated into neutral and acidic fractions on a DEAE-Sephadex column. Glycolipid fractions were obtained by acetylation and Florisil column chromatography, and the acetylated glycolipids were N-p-nitrobenzoylated by treatment with p-nitrobenzoyl chloride in pyridine at 60 degrees C for 6 h. Excess reagent and by-products were removed by solvent partition and gel filtration. The glycolipid derivatives were analyzed by their absorption at 254 nm on Zorbax SIL, a silica gel column, with a gradient of 0.5--7% isopropanol in hexane-chloroform (2 : 1, v/v) at a flow rate of 0.5 ml/min. The detector response was linear with up to 60 nmol of injected glycolipids. The practical lower limit of detection was about 50 pmol. The derivatives were separated on the basis of their sugar chains. Effluents corresponding to each peak were collected and analyzed further on the basis of their lipid portion on mu-Bondapak C18, a reversed phase column. This combined procedure was applied to the analysis of erythrocyte glycolipids. Samples containing as little as 20 micrograms of glycolipids could be analyzed by this method.     

Lipids of brush border membrane vesicles (BBMV) from Plutella xylostella resistant and susceptible to Cry1Ac delta-endotoxin of Bacillus thuringiensis

Plutella xylostella (PX) that were 130000-fold more resistant to Cry1Ac were selected from the susceptible strain and maintained in the laboratory. The LC50 of the susceptible strain (PXS) was 0.38 microg toxin/g diet, whereas that of the resistant strain (PXR) was 4800 microg toxin/g diet. Brush border membrane vesicles (BBMV) were prepared from both PXS and PXR. In ligand blot analysis, Cry1Ac bound to a 120-kDa protein of BBMV; however, the intensity of the band was almost equal in both strains of insect. Hence, we analyzed the lipid components of BBMV from PXS and PXR. BBMV lipids were fractionated into non-polar lipid, phospholipid, neutral glycolipid and acidic glycolipid. Neutral glycolipid content was substantially lower in the BBMV of PXR than of PXS. The same trend was observed when lipids were extracted from whole midgut instead of BBMV. Thin layer chromatography of midgut neutral glycolipids revealed the presence of more than seven components. Among the midgut neutral glycolipids, a possible hexasaccharylceramide and a possible trisaccharylceramide of PXR were less than half the level found in PXS. The other lipid fractions in PXR and PXS were similar to each other.     

Characterization of sulfated glucuronic acid containing glycolipids reacting with IgM M-proteins in patients with neuropathy

In some patients with neuropathy and plasma cell dyscrasia, the serum IgM M-proteins are known to bind to the myelin associated glycoprotein and to peripheral nerve glycolipids. We have isolated two acidic glycolipids which bind to the M-protein from human cauda equina by DEAE-Sephadex, Iatrobeads, and high performance liquid column chromatographies. The major acidic glycolipid migrated between GM1 and GD1a and the minor acidic glycolipid migrated between GD1a and GD1b. Their structures were elucidated by sugar analysis, enzymatic digestion, mild acid hydrolysis, permethylation, fast atom bombardment mass spectrometry, and NMR studies. Their core structure was confirmed to be paragloboside by high performance thin-layer chromatography-immunostaining using anti-paragloboside monoclonal antibody. Both acidic glycolipids lacked sialic acid but contained sulfated glucuronic acid as their acidic moiety. The sulfate group in the glucuronic acid was established by periodate oxidation and permethylation studies to be attached to the 3 position. The structures of the two acidic glycolipids are therefore consistent with the following: IV3GlcUA(3-sulfate)nLcOse4Cer and VI3GlcUA(3-sulfate)nLcOse6Cer. Additionally, the free carboxyl group on the glucuronic acid residue was shown to be necessary to bind the IgM M-proteins from neuropathy patients.     

Glycosphingolipids of human myometrium and endometrium and their changes during the menstrual cycle, pregnancy and ageing

The glycolipid composition of human myometrium and endometrium was examined at various stages of maturation and reproduction. The major neutral glycolipids of both myometrium and endometrium were identified by high-performance thin-layer chromatography as globo-series glycolipids, Gb3 and Gb4. The major acidic glycolipids (gangliosides) were identified similarly as GM3 and GD3, with lesser amounts of GM1, GD1a, and GT1b. During pregnancy, GD3 expression declined in both myometrium and endometrium, whereas GM3 expression increased. Reciprocal changes in GM3/GD3 expression were mirrored by appropriate changes in the glycosyltransferases required for their synthesis; alpha 2----3sialyltransferase activity increased approximately 3-fold during pregnancy, while alpha 2----8sialyltransferase activity declined to about 20%. The results focus attention on the glycolipids of uterine tissues, their regulation, and their possible role in reproduction and fertility.     

Sialylpentaosylceramide detected with anti-GM2 monoclonal antibody. Structural characterization and complementary expression with GM2 in gastric cancer and normal gastric mucosa

The ganglioside fraction of human gastric mucosa was analyzed with a newly established anti-GM2 monoclonal antibody KM531. Using this antibody, accumulation of GM2 was observed in all of four cases of gastric carcinoma. In all ganglioside fractions extracted from normal gastric mucosa obtained from eight cases of peptic ulcer GM2 itself was not detected, but three kinds of glycolipid showing slower mobility than GM2 on thin-layer plates were detected by immunostaining with KM531. These glycolipids were assigned as NGM-1, -2, and -3. They were completely lost in all carcinoma tissues and in non-cancerous gastric mucosa from two cases of gastric cancer, and they were also not detected in the ganglioside fraction of small or large intestine. Of these glycolipids, the major one, NGM-1, was isolated from the pooled ganglioside fraction of normal gastric mucosa obtained from cases of peptic ulcer. The structure was determined by proton nuclear magnetic resonance, negative ion fast atom bombardment-mass spectrometry, gas chromatography-mass spectrometry, and treatment with exoglycosidases and mild acid hydrolysis. The structure was GalNAc beta 1----4(NeuAc alpha 2----3) Gal beta 1----4GlcNAc beta 1----3 Gal beta 1----4Glc beta 1----1Cer, which has the same terminal sequence as GM2 but has internal neolacto series structure. This epitope was previously identified as Cad blood group antigen. The decrease of this glycolipid and the increase of GM2 was considered to be a cancer-associated change in gastric mucosa.     

Characterization of a series of novel fucose-containing glycosphingolipid immunogens from eggs of Schistosoma mansoni.

Lipid extracts of eggs, worms, and cercariae of the parasitic trematode Schistosoma mansoni have been shown to contain a large number of highly immunogenic glycolipids (Weiss, J. B., Magnani, J. L., and Strand, M. (1986) J. Immunol. 136, 4275-4282). Three fractions of schistosome egg glycolipids were selected on the basis of their reactivity with an anti-schistosome monoclonal antibody (128C3/3), which recognizes a developmentally regulated carbohydrate epitope present on both glycolipid and glycoprotein antigens from S. mansoni. These fractions were purified by silica gel chromatography and preparative high performance thin layer chromatography and characterized by monosaccharide, fatty acid, and linkage analysis with gas chromatography-mass spectrometry, as well as by positive and negative ion fast atom bombardment-mass spectrometry. The immunogens were shown to be glycosphingolipids having homologous structures based on a highly novel extension of glucosylceramide. Monosaccharide inhibition studies indicated that the epitope recognized by 128C3/3 residues in an outer region of the immunogens consisting of Fuc2GlcNAc (where Fuc is fucose) repeating units. The largest antigen characterized may have the following structure, based on the evidence presented in this paper. [sequence: see text] The evidence indicated the existence of a series of glycan structures created by deletions of one or more Fuc1----3 side chains from the above structure.     

The specific glycosphingolipid composition of human ureteral epithelial cells

Total non-acid and acid glycolipid fractions were isolated from epithelial cell scrapings and the non-epithelial residue of a human upper ureter. The glycolipid fractions were structurally characterized as total mixtures by thin-layer chromatography, mass spectrometry, and proton NMR spectroscopy. Selected structural information was also obtained on binding of monoclonal antibodies and bacteria to the thin-layer chromatograms. The major epithelial cell glycolipids were Glc beta 1-1ceramide (75%), dihexosylceramide (10%) and NeuAcLacceramide (10%). In addition, 8 minor glycolipids belonging to the blood group P, Lewis and ABO systems were identified. The major glycolipids of the non-epithelial residues were mono- and dihexosylceramides together with globotriaosyl- and globotetraosylceramides. The epithelial mono- and diglycosylceramide compounds had an unusual ceramide composition with mainly C18 and C20 trihydroxy long chain bases in combination with C22-C24 hydroxy fatty acids in contrast to the non-epithelial glycolipids which contained mainly C18 dihydroxy long chain bases in combination with C16-C24 non-hydroxy fatty acids.     

Inhibitory effects of gangliosides on immune reactions of antibodies to neutral glycolipids in liposomes

Specific immune damage to liposomes containing Forssman or globoside glycolipid was inhibited when the liposomes also contained ganglioside. The activity of a human monoclonal Waldenstr?m macroglobulin antibody to Forssman glycolipid was inhibited by each of three gangliosides tested, GM3, GD1a and GD1b. Inhibition of the monoclonal antibody was dependent on the amount of ganglioside in the liposomes, and was diminished by reducing the relative amount of ganglioside. Inhibition also correlated positively with the number of ganglioside sialic acid groups, with inhibition by GT1b greater than GD1a greater than GM3. Naturally occurring human antibodies to globoside glycolipid were detected in 18% (9 out of 50) of normal human sera tested. Immune damage to liposomes induced by each of the three highest-reacting human anti-globoside sera was blocked by liposomal GM3. We conclude that gangliosides can strongly influence immune damage to membranes induced by antibody interactions with adjacent neutral glycolipids.