Simultaneous determination of sugar incorporation into glycosphingolipids and glycoproteins.

We assessed inhibitors of glycosylation by simultaneous determination of [14C]Gal incorporated into glycosphingolipids and glycoproteins as well as of [3H]Leu incorporated into proteins of intact cells. After metabolic labeling in 96-well plates in the presence or absence of a test substance, cells were collected on glass-fiber filters. The lipid components were extracted from the filter and radioactivities of both extract and filter determined. The reliability of the procedure was tested with different drugs. Using the glucocerebroside synthetase inhibitor 1-phenyl-2-decanoylamino-3-morpholino-1-propanol (PDMP; 5 microM), glycolipid biosynthesis was shown to be reduced to 50% in the murine T-cell EL-4 6.1 line, whereas glycosylation of proteins was not disturbed. With 0.5 microM tunicamycin, the glycosylation of proteins was 50% of that in the control. The procedure was also able to detect various specific effects: the inhibition of protein glycosylation with D-glucosamine and castanospermine, the inhibition of glycosphingolipid biosynthesis with L-cycloserine, and a slight enhancement of glycosphingolipid biosynthesis with conduritol B epoxide and castanospermine. Within a series of N-acyl homologs of PDMP the inhibitory potency increased with chain length. In contrast, these homologs were equipotent by enzymatic in vitro assays.

Chromogenic labeling of milk oligosaccharides: purification by affinity chromatography and structure determination.

Oligosaccharides from human milk were derivatized with 4'-N,N-dimethylamino-4-amino-azobenzene (DAAB) by reductive amination and purified by affinity chromatography on immobilized antibodies followed by resolution of the retained antigenic molecules by adsorption chromatography on HPLC. The visibility to the naked eye and the favorable handling properties of the DAAB-oligosaccharides (desalting, quantification) offered distinctive advantages over underivatized oligosaccharides. Analysis by MS and NMR identified the two major antigens as the Lewis a active pentasaccharide and the Lewis b active hexasaccharide, respectively. Further derivation of DAAB-oligosaccharides by palmitoylamidoacetaldehyde generated glycolipid-like compounds suitable for immunological detection by in situ overlay techniques after separation by thin-layer chromatography.

Receptor analogs and monoclonal antibodies that inhibit adherence of Bordetella pertussis to human ciliated respiratory epithelial cells.

The adherence of Bordetella pertussis to human respiratory cilia is critical to the pathogenesis of whooping cough. To explore the development of agents that could interrupt adherence, the structure of the receptor on the ciliary surface was investigated. Using an in vitro adherence assay to human ciliated epithelial cells, galactose, lactose, and complex carbohydrates containing lactose eliminated adherence when preincubated with the bacteria. 10(-2) M galactose eluted adherent bacteria from cilia. B. pertussis and its two purified adhesins bound specifically to natural lactose-containing glycolipids in a TLC assay. mAbs to eukaryotic glycoconjugates with specificity for substituted galactose-glucose moieties blocked adherence when preincubated with ciliated cells. The carbohydrates that serve as receptors for B. pertussis on human cilia are galactose-glucose-containing glycolipids. Receptor analogs and anti-receptor antibodies effectively block adherence of B. pertussis to cilia and thus should be considered candidates for therapeutic intervention against disease.

Circulating antibodies to mouse laminin in Chagas disease, American cutaneous leishmaniasis, and normal individuals recognize terminal galactosyl(alpha 1-3)-galactose epitopes.

Sera from patients with American cutaneous leishmaniasis and Chagas disease and from monkeys infected with either Trypanosoma cruzi or Trypanosoma rhodesiense show, in RIAs, strong binding to mouse laminin. A distinct although weaker binding activity is also detected in normal human sera. The antibodies recognize a common carbohydrate epitope present on mouse laminin, which was assigned to a terminal galactosyl(alpha 1-3)-galactose group. Distinct crossreactions were observed with some other basement membrane proteins, rabbit glycosphingolipids, defucosylated human B blood group substance and components produced by some human tumor cells. Only little activity was, however, found on laminin obtained from human placenta. The data indicate that the antibodies arising in infectious diseases are stimulated by similar carbohydrate epitopes present on the surface of parasites. Tissue-specific occurrence of such epitopes may exist and explain the involvement of distinct tissues in autoimmune disorders.

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.

Unaltered immunocompetence in patients with non-disseminated breast cancer at the time of diagnosis.

Immunologic parameters were examined preoperatively in 104 patients with breast cancer, staged according to the TNM classification and in 95 age-matched healthy women. The immunologic evaluation in the peripheral blood included lymphocyte and monocyte counts, determination of E-rosette-forming T-lymphocytes (SER+) and B-lymphocytes (MER+), T-lymphocyte subsets defined with monoclonal antibodies (Leu-1, Leu-2a, Leu-3a) and with lectin fractionation (soybean agglutinin), lymphocyte transformation test with phytohemagglutinin (PHA) and concanavalin A (ConA), and colony formation of T-lymphocytes in agar (T-lymphocyte colony-forming cells, [TL-CFC]). Two age groups (Group A: 30-50 years; Group B: 51-70 years) and the different tumor stages (Stage I-IV) were analyzed. Patients and controls did not differ in the absolute numbers of lymphocytes, T- and B-cells. In patients of Group B, the absolute number of monocytes was increased slightly in Stage II and III and significantly in Stage IV (P less than 0.05). Similarly, the lymphocyte response to PHA was significantly reduced in Stage IV Group B only (P less than 0.05). ConA-induced lymphocyte proliferation and TL-CFC capacity were not different in patients and controls. In the small number of patients and age-matched controls in whom T-lymphocyte subsets were determined, the absolute numbers of T-cells with helper or suppressor phenotype as defined with Leu-3a, Leu-2a, or lectin fractionation with soybean agglutinin were similar. This study demonstrates that in patients with early breast cancer (Stage I-III), immunocompetence as defined by either functional in vitro studies or surface marker analysis is not significantly altered at the time of diagnosis. In contrast, patients with advanced disease (Stage IV) show a significant increase in the absolute number of monocytes and a depressed PHA responsiveness of mononuclear cells.

Glycosphingolipid-blotting: an immunological detection procedure after separation by thin layer chromatography.

A method for detecting glycosphingolipids (GSL) in situ after thin layer chromatography is described. The separated GSL are transferred by diffusion to nitrocellulose. The replica is incubated with poly- or monoclonal antibodies and bound antibodies are detected with second antibodies coupled to peroxidase. Advantages of the procedure are its speed, the non-radioactive detection method, and its suitability for screening applications. In addition, small scale affinity purification of antibodies from the replicas is possible. The presence of Forssman antigen in mouse tissues and the reaction of monoclonal antibodies with human GSL is demonstrated.

[Intact cellular immune response in patients with locally metastasizing breast carcinoma at the time of diagnosis]. / Intakte zelluläre Immunantwort bei Patientinnen mit lokoregional metastasierendem Mammakarzinom zum Zeitpunkt der Diagnose.

Reduced cellular immune response is well documented in patients with advanced breast cancer. To investigate immunocompetence at the time of diagnosis, 104 patients with breast cancer staged according to the TNM classification were studied preoperatively and compared with 95 age matched healthy women. Tests of blood mononuclear leukocytes included lymphocyte and monocyte counts, determination of rosette forming T (SER +) and B (MER +) lymphocytes, T lymphocyte subsets defined with monoclonal antibodies (Leu-1, Leu-2a, Leu-3a) and with lectin fractionation (soybean agglutinin, SBA), lymphocyte transformation tests with PHA and ConA and colony formation of T cells in agar (TL-CFC). Two age groups (A: 30-50, B: 51-70 years) and the different tumor stages (I-IV) were analyzed. Patients and controls did not differ in absolute numbers of lymphocytes, T and B cells. In patients of group B the absolute number of monocytes was slightly increased in stages II and III and significantly in stage IV (p less than 0.025). Similarly, the lymphocyte response to PHA was significantly reduced in stage IV group B only (p less than 0.05). ConA induced lymphocyte proliferation and TL-CFC capacity were not different in patients and controls. In the small number of patients and age matched controls, in whom T lymphocyte subsets were determined, the relative numbers of T cells with helper or suppressor phenotype as defined with Leu-3a, Leu-2a, or SBA were similar. In conclusion, in breast cancer, at the time of diagnosis, blood T lymphocyte populations and functions are not altered except in elderly patients with disseminated disease. The monocytosis and reduced PHA responsiveness observed in the latter group may be related phenomena.

Sphingosine determination at the picomole level using dimethylaminoazobenzene sulphonyl chloride.

A sensitive method (lower detection limit 5 picomoles) is proposed for the determination of sphingoid bases liberated from mammalian glycosphingolipids by acid hydrolysis. The azo dye 4-dimethylaminoazobenzene-4'-sulfonyl chloride reacts with the primary amino group of the sphingosine bases, forming a stable derivative. Excess reagent, which is degraded during the derivatization, and free amino sugars as common hydrolysis products of glycosphingolipids are completely separated by reversed-phase high-performance liquid chromatography. This method was applied to the determination of the glycosphingolipid content of mouse spleen and thymus.

Ganglioside patterns: new biochemical markers for human hematopoietic cell lines.

The ganglioside patterns from a representative collection of 20 human B-cell, T-cell, null cell, myeloid cell, and early erythroid cell lines were determined. Radioactive sugar-labeled gangliosides from cultured cells were extracted, analyzed, and quantitated by high-performance thin-layer chromatography (HPTLC) and high-pressure liquid chromatography, essentially according to the polarity of the oligosaccharide chain. The ganglioside labeling patterns of the human cell lines were in some cases extremely complex, since more than 100 components could be separated upon two-dimensional HPTLC, e.g., in the case of a promyelocytic cell line. Each type of cell showed a characteristic pattern: Null cell lines were much less complex than T-cell lines, and myeloid and erythroid lines exhibited characteristic patterns as well. Although clearly distinguishable from all other cell lines, the B-cell lines showed a high degree of heterogeneity. Therefore, gangliosides can be expected to serve as additional markers to establish the origin, of a cell line or to classify pathologic cell populations.

Iso-branched 2- and 3-hydroxy fatty acids as characteristic lipid constituents of some gliding bacteria.

The fatty acids present in the total hydrolysates of several gliding bacteria (Myxococcus fulvus, Stigmatella aurantiaca, Cytophaga johnsonae, Cytophaga sp. strain samoa and Flexibacter elegans) were analyzed by combined gas-liquid chromatography and mass spectrometry. In addition to 13-methyl-tetradecanoic acid, 15-methyl-hexadecanoic acid, hexadecanoic acid, and hexadecenoic acid, 2- and 3-hydroxy fatty acids comprised up to 50% of the total fatty acids. The majority was odd-numbered and iso-branched. Small amounts of even-numbered and unbranched fatty acids were also present. Whereas 2-hydroxy-15-methyl hexadecanoic acid was characteristic for myxobacteria, 2-hydroxy-13-methyl-tetradecanoic acid, 3-hydroxy-13-methyl-tetradecanoic acid, and 3-hydroxy-15-methyl-hexadecanoic acid were dominant in the Cytophaga-Flexibacter group.

Metabolic carbohydrate-labelling of glycolipids from mouse splenocytes. Mitogen-stimulated B and T cells show different labelling patterns.

Splenic lymphocytes from CBA/J, AKR/A/J, BALB/c/A, C57/BL/6J, C3H/HeJ and C3H/Tif nu/nu mice and B lymphocyte or T lymphocyte preparations derived from CBA/J mouse spleen were cultivated in the presence of either concanavalin A, phytohemagglutinin, Salmonella minnesota R595 lipopolysaccharide or Proteus mirabilis soluble lipoprotein. The mitogens stimulated the incorporation of [14C]galactose into acid-insoluble cell material with the same specificity for B or T cells as that known for thymidine incorporation. The glycolipids extracted from mitogen-activated, carbohydrate-labelled B or T cells were compared by thin-layer chromatography and characteristic differences between B and T cells were noted in the ganglioside as well as in the neutral glycolipid fractions. In addition, subsets of B or T cells, namely lipopolysaccharide-responsive or lipoprotein-responsive B-cell populations or nylon-purified T cells may be recognized by characteristic neutral glycolipid bands.

Association of the glycolipid pattern with antigenic alterations in mouse fibroblasts transformed by murine sarcoma virus.

The level of the neutral glycolipid, Galnac beta 1 leads to 4 Gal beta 1 leads to 4Glc leads to Cer (asialo GM2), in BALB/c 3T3 mouse fibroblasts transformed by Kirsten murine sarcoma virus (3T3KIMSV) was greatly increased compared to the nontransformed parental cells (3T3). This elevated chemical quantity was found to be localized on the surface of intact cells and accessible to external reagents, as detected by immunofluorescence and labeling with galactose oxidase: NaB3H4. Furthermore, immunization of rabbits with 3T3KiMSV cells but not with 3T3 cells resulted in antibody production against asialo GM2. These results demonstrate the potential usefulness of glycolipids as tumor-associated cell surface markers.