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PubMed1972

Characterization and in vivo production of three glycolipids from Candida Bogoriensis: 13-glucopyranosylglucopyranosyloxydocosanoic acid and its mono- and diacetylated derivatives.

Three glycosides of 13-hydroxydocosanoic acid isolated from Candida bogoriensis were characterized by quantitating the amount of carbohydrate, acetate, and hydroxy acid in each, and by gas-liquid chromatography and mass spectrometry of their methyl ester, trimethylsilyl ether derivatives. One of the glycosides was the diacetylated derivative of 13-glucosylglucosyloxydocosanoic acid previously characterized by Tulloch, Spencer, and Deinema (Can. J. Chem., 46: 345 [1968]), in which the disaccharide had the beta(1 --> 2) sophorose linkage and the acetyl groups were attached to the 6' and 6" positions of the glucose residues. The other two glycosides were 13-glucosylglucosyloxydocosanoic acid and its monoacetylated derivative. A comparison of the mass spectra of derivatives indicates that the acetyl group of the monoacetyl lipid is on the internal glucose. Methyl 13-glucosyloxydocosanoate was produced by acid hydrolysis of the methyl ester of the unacetylated glycolipid and was characterized by the same techniques as the other glycolipids. Time course of production of the three glycolipids is consistent with the diacetylated derivative being the first extra-cellular product and the other two glycolipids being formed by deacetylation. 13-Hydroxy[13-(3)H]docosanoic acid, methyl 13-hydroxy[13-(3)H]docosanoate, and 9-hydroxy[11,12-(3)H]-stearic acid were each incorporated into the glycolipid fraction.

Candida↗
PubMed1984

Glycolipid accumulation in bronchoalveolar space in adult respiratory distress syndrome.

Surfactant lipids in the alveolar space are believed to play an important role in normal respiratory function. Although the surface-active phospholipids have been extensively studied, the possible role of glycolipids in the surfactant remains to be explored. We have studied the glycolipid composition of cell-free bronchoalveolar lavage from healthy subjects and from adult patients with respiratory distress syndrome. Glycolipids were barely detectable in bronchoalveolar lavage from healthy subjects. However, in adult respiratory distress syndrome, the amount of glycolipid relative to phospholipid was increased by more than twenty times. These lipids, identified as lactosylceramide (galactose-glucose-ceramide) and paragloboside (galactose-N-acetylglucosamine-galactose-glucose-ceramide), may prove to be sensitive markers of lung injury. Since the glycolipids decreased the surface activity of surfactant in vitro, their potential role in the pathogenesis of adult respiratory distress syndrome should be considered.

Carbohydrates↗
PubMed1980

Role of sialic acid in the macrophage glycolipid receptor for MIF.

Acidic glycolipids from guinea pig macrophages enhance the response of macrophages to migration inhibitory factor (MIF), suggesting a role of glycolipid receptors for this lymphocyte mediator. Neuraminidase treatment of these glycolipids results in the loss of their biologic activity. This activity remains intact after incubation of the glycolipids with beta-galactosidase. In order to investigate whether sialic acid is essential for the macrophage's response to MIF, macrophages were incubated with neuraminidase. Neuraminidase treatment of peritoneal exudate cells results in the abrogation of macrophage responsiveness to MIF. Other exoglycosidases such as beta-galactosidase and beta-glucosidase had no effect upon the macrophage response. The effect of neuraminidase was found to be reversible within 18 hr. These experiments suggest that macrophage glycolipids containing sialic acid are components of the macrophage receptor for MIF.

Animals↗
PubMed1995

Glycolipid ligands for selectins support leukocyte tethering and rolling under physiologic flow conditions.

Selectin interactions with glycolipids have been examined previously under static conditions, whereas physiologic interactions mediated by selectins take place under flow. We find that under physiologic flow conditions, sialyl Lewis(x) (sLe(x)) glycolipid and sialyl Lewisa (sLe(a)) neoglycolipid support tethering and rolling adhesions of Chinese hamster ovary (CHO) cells expressing E-selectin and lymphoid and myeloid cells expressing L-selectin. These selectin-mediated adhesions persist at the highest shear stresses that occur in postcapillary venules in vivo and occur at lower site densities than found for sLe(x) on neutrophils. The interactions are Ca(2+)-dependent and can be specifically and completely blocked with anti-selectin mAbs. Asialo nonfucosylated glycolipids are inactive, and sulfatide supports weak tethering, but not rolling, of L-selectin-expressing cells. Rolling velocities and resistance to detachment are related to the glycolipid site density and fall within the range measured for neutrophil and myeloid cell rolling on substrates containing purified selectins. These observations are the first indication that glycolipids can interact with selectins in physiologic flow conditions, and can contribute to rolling adhesions.

Animals↗
PubMed1994

Presence of antiheart and antiskeletal muscle glycolipid autoantibodies in the sera of patients with chagasic cardiopathy.

OBJECTIVE: To characterize biochemically and isolate the skeletal and heart muscle cell epitope recognized by the autoantibodies present in the serum of chronically infected Trypanosoma cruzi patients. Secondly, to use that epitope in an immunoenzymatic assay for determining differences in antibody titre among Chagas' and other protozoan and heart diseases and between asymptomatic and cardiopathic chagasic patients. DESIGN: Isolated human skeletal and heart muscle cells were treated with organic solvents, pronase, neuraminidase and sodium metaperiodate before immunofluorescence assay. Glycolipids were extracted from human skeletal muscle for ELISA. PATIENTS: Sera were collected from 155 patients with positive serology for T cruzi infection; 44 healthy blood bank donors; and from patients after heart transplantation (16 patients), during the first month after cardiac infarction (eight) or cardiotomy (10), dilated myocardiopathy (21), leishmaniasis (12), acute toxoplasmosis (four) and hyperthyroid ophthalmopathy (five). MAIN RESULTS: Immunofluorescence assay revealed that the chagasic sera recognized epitopes that appeared to be glycolipid in nature. ELISA showed that the chagasic sera contained a higher titre of antiskeletal muscle glycolipid antibodies than the control sera and that, in the chagasic population, antibody titre was significantly higher in patients with heart failure than in asymptomatic subjects or in those presenting only electrocardiographic abnormalities. CONCLUSIONS: The skeletal and heart muscle epitope recognized by antibodies present in the sera of chagasic patients has the characteristics of a glycolipid. ELISA with glycolipids extracted from human skeletal muscle indicated that chagasic patients presented a higher antibody titre and that patients with heart failure showed a titre significantly higher than those who were asymptomatic or with electrocardiographic abnormalities, suggesting that those antibodies could be immunological markers and even predictors of heart failure in Chagas' disease.

Autoantibodies↗
PubMed1994

N-butyldeoxygalactonojirimycin inhibits glycolipid biosynthesis but does not affect N-linked oligosaccharide processing.

We have previously reported that the imino sugar N-butyldeoxynojirimycin (NB-DNJ) inhibits glycolipid biosynthesis, in addition to its known activity as an inhibitor of the N-linked oligosaccharide processing enzyme alpha-glucosidase I. In an attempt to dissociate these two activities and identify an inhibitor which was more selective for the glycolipid biosynthetic pathway, several imino sugars have been N-alkylated and tested for inhibitory activity. The galactose analogue N-butyldeoxygalactonojirimycin (NB-DGJ) was found to be a potent inhibitor of glycolipid biosynthesis but in contrast to NB-DNJ had no effect on the maturation of N-linked oligosaccharides or on lysosomal glucocerebrosidase. The effect of increasing N-alkyl chain length on glycolipid inhibition was investigated. Nonalkylated DGJ, the N-methyl and N-ethyl derivatives, were noninhibitory. However, N-propylation resulted in partial inhibition while the N-butyl and N-hexyl derivatives resulted in maximal inhibition. Increasing alkyl chain length also resulted in increased potency of glucosyltransferase inhibition. In an in vitro Gaucher's disease model NB-DGJ was as effective as NB-DNJ in preventing glycolipid storage and may represent a more selective potential therapeutic agent than NB-DNJ for the management of this and other glycosphingolipidoses.

1-Deoxynojirimycin↗
PubMed1993

Alpha- and beta-xylosides alter glycolipid synthesis in human melanoma and Chinese hamster ovary cells.

beta-D-Xylosides are often used to competitively inhibit proteoglycan synthesis by serving as primers for free glycosaminoglycan (GAG) chain assembly. Quite unexpectedly, we found that when human melanoma cells and Chinese hamster ovary cells are labeled with [3H] galactose in the presence of 4-methyl umbelliferyl beta-D-xyloside (Xyl beta 4MU), a large portion of the labeled acceptor does not consist of the expected GAG chains, but of the novel GM3 ganglioside-like structure: Sia-alpha 2,3-[3H]Gal beta 1, 4Xyl beta 4MU. Moreover, formation of this derivative is associated with an inhibition of glycosphingolipid synthesis by up to 78% without affecting synthesis of other [3H]Gal-labeled glycoconjugates. Inhibition occurs rapidly and equally for all glycolipid species and is partially abrogated by brefeldin A. Inhibition requires the addition of a single galactose residue to the xyloside within the lumen of the Golgi apparatus. This addition appears to be carried out by galactosyl transferase I that normally synthesizes the core region of GAG chains. Although alpha-xyloside does not inhibit proteoglycan synthesis, it is galactosylated, but not sialylated, and is nearly as effective as a beta-xyloside at inhibiting glycolipid biosynthesis. Similar results were obtained for human macrophage U937, and differentiated or undifferentiated PC12 cells. However, in neuroblastoma cell line MR23, no low molecular weight xyloside products were made and glycolipid synthesis was not inhibited. These results suggest that some of the previously documented effects of beta-xylosides might result, in part, from their inhibition of glycolipid synthesis. The mechanism of inhibition is not a direct competition for glycolipid synthesizing enzymes; rather, it is an unexplained result of formation of Gal beta 1,4Xyl-1 (alpha or beta)4MU.

Animals↗
PubMed1998

Selective ability of mouse CD1 to present glycolipids: alpha-galactosylceramide specifically stimulates V alpha 14+ NK T lymphocytes.

Mouse CD1 (mCD1) glycoproteins are known to present peptides, while human CD1 molecules present glycolipids. In mice, mCD1-autoreactive NK T cells play critical roles in various immune responses, through the secretion of high amounts of cytokines. This study was initiated to determine whether glycolipids are involved in the autorecognition of mCD1 by NK T cells. Alpha-galactosylceramide (alpha-GalCer) was the only glycolipid tested capable of eliciting an mCD1-restricted response by splenic T cells. Moreover, splenic T cells derived from mCD1-deficient mice were not stimulated by alpha-GalCer, suggesting that the responsive T cells are selected by mCD1. Using cytoflow techniques, we confirmed that, in response to alpha-GalCer, IFN-gamma-secreting cells displayed an NK T cell phenotype. The predominance of IFN-gamma vs IL-4, however, is determined by the type of mCD1+ APC, suggesting the potential for APC regulation of cytokine production by NK T cells. Among a panel of 10 mCD1-autoreactive T cell hybridomas, only the ones that express the typical V alpha 14 J alpha 281 TCR rearrangement of NK T cells responded to alpha-GalCer. Fixation or treatment of mCD1+ APCs with an inhibitor of endosomal acidification and the use of mCD1 mutants unable to traffic through endosome still allowed alpha-GalCer to stimulate NK T cells. Thus, endosomal trafficking and Ag processing are not required for glycolipid recognition. In summary, alpha-GalCer might be the autologous ligand, or a mimic of a glycolipid ligand, involved in the mCD1-mediated stimulation of NK T cells.

Animals↗
PubMed1998

Glycolipid-protein interaction in the mechanism of signal transduction: studies with a photoactivable ganglioside analogue.

An increasing body of evidence suggests that glycolipid domains are present on the plasma membrane surface of mammalian cells and play a key role in signal transduction. We have investigated the modulation of glycolipid-protein interaction consequent to a specific event occurring at the plasma membrane. For this purpose, a new photoactivable, radioactive derivative of GM1 ganglioside, carrying a phenyldiazirine fatty acid labelled with 125I, has been used with rat cerebellar granule cells in culture. Upon incubation of photoactivable GM1 with the cells followed by illumination, several proteins become radioactive and were detectable on the two dimensional-electrophoresis, which points to their interaction with the ganglioside. Upon addition of cytotoxic doses of glutamate, known to induce indirectly the activation of protein kinase C (PKC), one of the proteins crosslinked by photoactivable GM1 in control cells of molecular mass about 92 kDa and pI about 4, was not anymore detectable; this suggests its exclusion from the glycolipid domains. On the contrary, another protein, of about 15 kDa and pI 6.5, previously not crosslinked, was interacting with the ganglioside derivative after glutamate treatment. Comparable effects were exerted by phorbol-2-myristate-3-acetate, which directly induces the activation of PKC. These results show that PKC activation, a key step of inbound trans-membrane signalling, affects the interaction between glycolipids and proteins at the plasma membrane surface, possibly within a mixed domain. The dynamic modulation of ganglioside-protein interaction may affect the involvement of glycolipid domains in membrane-located events such as signal transmission and lipid/protein sorting.

Animals↗
PubMed1980

Interactions of phospholipid vesicles with rat hepatocytes in vitro. Influence of vesicle-incorporated glycolipids.

We examined the interaction of glycolipid-containing phospholipid vesicles with rat hepatocytes in vitro. Incorporation of either N-lignoceroyldihydrolactocerebroside or the monosialoganglioside, GM1, enhanced liposomal lipid uptake 4-5-fold as judged by the uptake of radioactive phosphatidylcholine as a vesicle marker. Cerebroside enhanced phospholipid uptake only when incorporated into dimyristoyl, but not into egg phosphatidylcholine vesicles. The lack of cerebroside effect in egg phosphatidylcholine-containing vesicles appeared to be due to a limited exposure of the carbohydrate part of the glycolipid as suggested by the reduced agglutinability of those vesicles by Ricinus communis agglutinin. In contrast to the results with radioactive phosphatidylcholine, we observed only a 20% increase in vesicle-cell association as a result of glycolipid incorporation, when a trace amount of [14C]cholesteryloleate served as a marker of the liposomal lipids or when using the fluorescent dye, carboxyfluorescein, as a marker of the aqueous space of the vesicles. By the same token, intracellular delivery of vesicle-contents was only slightly enhanced (approx. 10%). The discrepancy between the association with the cells of phosphatidylcholine on the one hand and cholesteryloleate or entrapped marker on the other suggests different mechanisms of uptake for these markers. Our results are compatible with the notion that the main effect of incorporation of glycolipids into the vesicle is the enhancement of exchange or transfer of phospholipid molecules between vesicles and cells. Incubation of the cells with galactose or lactose, prior to addition of vesicles, suggests that this enhanced phospholipid exchange or transfer involves specific recognition of the terminal galactose residues of the glycolipid vesicles by a receptor present on the plasma membranes of hepatocytes.

Animals↗
PubMed1983

Localization of globoside and Forssman glycolipids on erythrocyte membranes.

Using the freeze-etch technique, the membrane localization of globoside, a principal glycolipid in human erythrocytes, and Forssman antigen, the chief glycolipid in sheep erythrocytes was evaluated using ferritin and colloidal gold as morphological markers for rabbit antibodies prepared against these glycolipids. Brief trypsinization of human red cell ghosts markedly aggregated intramembranous particles and permitted labeling of globoside, which appeared in a clustered arrangement. The aggregates of ferritin-anti-globoside differed from those of ferritin-wheat germ agglutinin, a label for glycophorin, which corresponded with the aggregates of intramembranous particles. Double-labeling of human trypsinized ghosts with anti-globoside/ Staphylococcal protein A-colloidal gold and ferritin-wheat germ agglutinin indicated that the patterns of labeling were different and that the aggregates of globoside did not bear a direct relationship to the intramembranous particles, which represent transmembrane proteins. Resealed sheep erythrocyte ghosts labeled with ferritin-conjugated rabbit anti-Forssman showed small clusters of Forssman glycolipid on the erythrocyte surface, which could be markedly aggregated with a second goat anti-rabbit antibody, indicating relative mobility of the small glycolipid domains. The distribution of ferritin-anti-Forssman label in sheep ghosts treated at pH 5.5 to aggregate intramembranous particles also did not show definite correspondence between intramembranous particles and the clusters of ferritin-anti-Forssman.

Antigens, Heterophile↗
PubMed1984

A fluorimetric determination of the activity of glycolipid transfer protein and some properties of the protein purified from pig brain.

The fluorimetric method of Correa-Freire et al. (Correa-Freire, M.C., Barenholz, Y. and Thompson, T.E. (1982) Biochemistry 21, 1244-1248) to measure glucosylceramide transfer between phospholipid bilayers has been applied to the determination of the activity of glycolipid transfer protein purified from pig brain. The transfer of pyrene-labeled galactosylceramide (PyrGalCer) from donor to acceptor vesicles was measured by a decrease in the intensity ratio of eximer (E) to excited monomer (M). A sensitive determination of the glycolipid transfer activity is possible by the fluorimetric method without separation of the donor and acceptor vesicles. The newly developed fluorimetric assay of glycolipid transfer protein was used to study the effects of N-ethylmaleimide, HgCl2 and sugars on the transfer activity. The treatment with N-ethylmaleimide inactivated the activity to about 40%. The activity was almost completely inactivated by the treatment with HgCl2. Monosaccharides and methyl-alpha-D-glucoside had no inhibitory effect on the transfer activity. A marked and immediate drop of the E/M ratio was observed by the addition of glycolipid transfer protein to vesicles containing PyrGalCer at a protein-to-PyrGalCer molar ratio of 1.56:1. The result suggests a complex formation of glycolipid transfer protein with PyrGalCer.

Animals↗
PubMed2006

Membrane interaction and activity of the glycolipid transfer protein.

In this study we have addressed the ability of the glycolipid transfer protein (GLTP) to transfer anthrylvinyl-galactosylceramide at different pH and sodium chloride concentrations, and the ability of three different mutants to transfer the fluorescently labeled galactosylceramide between donor and acceptor model membranes. We constructed single tryptophan mutants with site-directed mutagenesis where two of the three tryptophan (W) of wild-type human GLTP were substituted with phenylalanine (F) and named W85 GLTP (W96F and W142F), W96 GLTP (W85F and W142F) and W142 GLTP (W85F and W96F) accordingly. Wild-type GLTP and W96 GLTP were both able to transfer anthrylvinyl-galactosylceramide, but the two variants W85 GLTP and W142 GLTP did not show any glycolipid transfer activity, indicating that the tryptophan in position 96 is crucial for transfer activity. Tryptophan fluorescence emission showed a blue shift of the maximal emission wavelength upon interaction of glycolipid containing vesicle with wild-type GLTP and W96 GLTP, while no blue shift was recorded for the protein variants W85 GLTP and W142 GLTP. The quantum yield of tryptophan emission was highest for the W96 GLTP protein whereas W85 GLTP, W142 GLTP and wild-type GLTP showed a lower and almost similar quantum yield. The lifetime and anisotropy decay of the different tryptophan mutants also changed upon binding to vesicles containing galactosylceramide. Again wild-type GLTP and W96 GLTP showed similar behavior in the presence of vesicles containing glycolipids. Taken together, our data show that the W96 is involved not only in the activity of the protein but also in the interaction between the protein and glycolipid containing membranes.

Anisotropy↗
PubMed1996

Comparison of A60 and three glycolipid antigens in an ELISA test for tuberculosis.

OBJECTIVES: To compare the diagnostic usefulness in tuberculosis of the serodiagnostic enzyme-linked immunosorbent assay (ELISA) kit A60 (Anda Biologicals, Strasbourg, France) and of our domestic ELISA based on three purified cell wall glycolipid antigens. METHODS: The presence and concentrations of IgG and IgM anti-A60 antibodies and anti-LOS, anti-DAT and anti-PGLTb1 antibodies against the glycolipid antigens were determined by ELISA in 50 HIV-seronegative and 46 HIV-seropositive patients, with documented active tuberculosis. The specificity of these ELISAs was determined with use of sera from 50 healthy blood donors, 29 patients with non-mycobacterial pulmonary diseases and 24 HIV-positive patients with disseminated Mycobacterium avium infection. RESULTS: With a calculated cut-off for each antigen and immunoglobulin that gave a specificity higher than or equal to 98%, the cumulative ELISA results showed that only 36.5% of the patients with tuberculosis had a positive response in the A60 test, as compared with 84.4% who showed a response to the three glycolipid antigens (p<0.001). This striking difference persisted when the cumulative sensitivities were calculated according to the HIV status of the patients and the localization of tuberculosis. The anti-A60 antibody (IgG and IgM) levels and the degree of sensitivity of the ELISA for detection of A60 antigen were always lower in HIV-positive patients with pulmonary and extrapulmonary tuberculosis than in HIV-negative patients with tuberculosis. The sensitivity of A60 ELISA was further decreased in HIV-positive patients with low CD4+ lymphocytes counts, in contrast to the results with the three glycolipid antigens. CONCLUSIONS: These results show the limitations of the A60 ELISA, and confirm the potencies of the glycolipid antigens in serodiagnosis of tuberculosis in HIV-positive and HIV-negative patients.

Journal Article↗
PubMed1995

Initiation of chemical studies on the immunoreactive glycolipids of adult Ascaris suum.

There is a general lack of basic information concerning one class of glycoconjugate, the glycolipids, from parasitic nematodes. As the prototype, the neutral glycolipid fraction derived from adult males of Ascaris suum was investigated as to its chromatographic, differential chemical staining, antigenic and chemical properties. The thin-layer chromatography-resolved neutral fraction glycolipids could be classified into components of fast and slow migrating band groups. Immunoreactivity was restricted to the latter as detected by IgG and IgM anti-neutral fraction glycolipid antibody levels in serial infection sera of mice. Similarities of chromatography, antigenicity and serological cross-reactivity have been extended to the neutral glycolipid fractions of other parasitic nematodes: Litomosoides carinii and Nippostrongylus brasiliensis. Chemical, differential chemical staining and enzymatic analyses identified the Ascaris suum antigenic, slow migrating band group of components as amphoteric glycosphingolipids, and not the originally hypothesized glycoglycerolipids or glycosylphosphatidylinositols, that contained typical neutral monosaccharide constituents and a zwitterionic phosphodiester linkage, most probably phosphocholine. Glycosphingolipid-immunoreactivity is eliminated on cleavage of the zwitterionic phosphodiester linkage by hydrofluoric acid treatment.

Animals↗
PubMed1985

Net mass transfer of galactosylceramide facilitated by glycolipid transfer protein from pig brain: a monolayer study.

A net mass transfer of galactosylceramide (GalCer) and galactosyldiacylglycerol (GalDG) is catalyzed by the glycolipid transfer protein from pig brain. GalCer and GalDG are transferred from a monolayer to phosphatidylcholine vesicles in the subphase or from a glycolipid monolayer to a phosphatidylcholine monolayer. No transfer of phosphatidylcholine is measured under these conditions. It is found that the glycolipid transfer protein functions as a carrier and that glycolipid is bound to less than 50% of the transfer protein. The presence of lipid-free proteins fits with the proposed mechanism of net mass transfer. The glycolipid transfer is influenced by the fluidity of the lipid interface and by the matrix lipid of the interface. GalCer transfer is stimulated in the presence of GalDG.

Animals↗
PubMed1977

Isoantigenic expression of Forssman glycolipid in human gastric and colonic mucosa: its possible identity with "A-like antigen" in human cancer.

The heterogenetic Forssman antigen is a glycosphingolipid, a ceramide pentasaccharide with the structure GalNAcalpha1-->3GalNAcbeta1-->3Galalpha1-->4Galbeta1-->4Glc-->ceramide. Forssman-positive animals are capable of synthesizing this compound in tissues or in erythrocytes, in contrast to the Forssman-negative species, including humans, which are incapable of adding the last carbohydrate in the sequence of the Forssman antigen, namely alphaGalNAc. The Forssman glycolipid and its precursor globoside were examined in twenty-one samples of surgically extirpated gastrointestinal mucosa and tumors derived therefrom. The results revealed that a few patients had chemically and immunologically detectable levels of the Forssman glycolipid as a normal component of their gastrointestinal mucosa (F(+) population); in contrast, the majority of patients did not contain this glycolipid in their normal mucosa (F(-) population). Whereas the F(-) population included blood groups A, B, and O, the F(+) population did not correspond to blood group A. The Forssman status in tumors taken from the F(+) or F(-) population showed the following striking features: (i) all tumors derived from F(-) mucosa possessed Forssman glycolipid, whereas (ii) none of the tumors originating in F(+) mucosa contained Forssman glycolipid. Globoside, the immediate precursor of Forssman antigen, was distributed equally among F(+) and F(-) mucosa and the tumors derived therefrom. Thus, the expression of Forssman antigen in gastrointestinal mucosa appears akin to that of an isoantigen. Furthermore, the Forssman antigen that appears in tumors of the F(-) population could represent a human tumor-associated antigen. In view of the strong crossreactivity of Forssman antigen with blood group A determinants, the appearance of Forssman antigen in human tumors could be related to the "A-like antigen" (or "neo-A antigen") of human tumors reported previously [Hakomori, S., Koscielak, J., Black, K. J. & Jeanloz, R. W. (1967) J. Immunol. 98, 31-38; Häkkinen, I. (1970) J. Natl. Cancer Inst. 44, 1183-1193].

ABO Blood-Group System↗
PubMed1994

A mouse B16 melanoma mutant deficient in glycolipids.

Mouse B16 melanoma cell line, GM-95 (formerly designated as MEC-4), deficient in sialyllactosylceramide was examined for its primary defect. Glycolipids from the mutant cells were analyzed by high-performance TLC. No glycolipid was detected in GM-95 cells, even when total lipid from 10(7) cells was analyzed. In contrast, the content of ceramide, a precursor lipid molecule of glycolipids, was normal. Thus, the deficiency of glycolipids was attributed to the first glucosylation step of ceramide. The ceramide glucosyltransferase (EC 2.4.1.80) activity was not detected in GM-95 cells. There was no significant difference of sialyllactosylceramide synthase activity, however, between GM-95 and the parental cells. The deficiency of glycolipids in GM-95 cells was associated with changes of the cellular morphology and growth rate. The parental cells showed irregular shapes and tended to overlap each other. On the other hand, GM-95 cells exhibited an elongated fibroblastic morphology and parallel arrangement. The population-doubling times of GM-95 and the parental cells in serum-free medium were 28 hr and 19 hr, respectively.

Animals↗