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PubMed1997

Structures of phenolic glycolipids from Mycobacterium kansasii.

From the lipid fraction of cells of Mycobacterium kansasii, four phenolic glycolipids K5, K6, K7 and K8, were isolated, in addition to three known phenolic glycolipids KI, KII and KIV. K5 was identified as a tetraglycosyl phenolic glycolipid whose sugar moiety was 2,6-dideoxy-4-O-methyl-L-alpha-arabinohexopyranosyl(1-->3)-4-O-pro pionyl-2-O-methyl-L-alpha-fucopyranosyl(1-->3)-2-O-methyl-L-alpha-rhamno pyranosyl-(1-->3)-2,4-di-O-methyl-L-alpha-rhamnopyranosyl(1-->) and phenolic glycolipid K6 as deacetyl-KI. Glycolipids K7 and K8 were triglycosyl phenolic glycolipids having the sugar moieties of 2-O-methyl-L-alpha-fucopyranosyl(1-->3)-2-O-methyl-L-alpha-rhamnopyranos yl(1-->3)-2,4-di-O-methy-L-alpha-rhamnopyranosyl(1-->) and 2-O-methyl-L-alpha-fucopyranosyl(1-->3)-2-O-methyl-L-alpha-rhamnopyranos yl(1-->3)-2-O-methyl-L-alpha-rhamnopyranosyl(1-->), respectively. Phenolic glycolipids K6 and K7 have been referred to as controlled degradation products of phenolic glycolipid KI previously. Also isolated was 5-mycolyl-beta-arabinofuranosyl(1-->2)-5-mycolyl-alpha-ar abinofurnosyl(1-->1')-glycerol, an analogue of glycolipid ai, originally isolated from Mycobacterium avium-Mycobacterium intracellulare complex, having mycolic acids of M. kansasii.

Antigens, Bacterial↗
PubMed1984

Chemical synthesis and serology of disaccharides and trisaccharides of phenolic glycolipid antigens from the leprosy bacillus and preparation of a disaccharide protein conjugate for serodiagnosis of leprosy.

We examined the structural requirements within the species-specific 3,6-di-O-methyl-beta-D-glucopyranosyl-(1 leads to 4)-2,3-di-O-methyl- alpha-L-rhamnopyranosyl-(1 leads to 2)-3-O-methyl-alpha-L-rhamnopyranose unit of the phenolic glycolipid I antigen of Mycobacterium leprae for binding to anti-glycolipid immunoglobulin M from human leprosy sera. We used chemically defined, partially deglycosylated fragments of phenolic glycolipid I, two other minor M. leprae-specific phenolic glycolipids (those containing 6-O-methyl-beta-D-glucopyranosyl-(1 leads to 4)-2,3-di-O-methyl-alpha- L-rhamnopyranosyl-(1 leads to 2)-3-O-methyl-alpha-L-rhamnopyranose and 3,6-di-O-methyl-beta-D-glucopyranosyl-(1 leads to 4)-3-O-methyl-alpha- L-rhamnopyranosyl-(1 leads to 2)-3-O-methyl-alpha-rhamnopyranose units), and phenolic glycolipids from other mycobacteria. Additionally, the trisaccharide of phenolic glycolipid I, the 3,6-di-O-methyl-beta-D-glucopyranosyl-(1 leads to 4)-2, 3-di-O-methyl-alpha-L-rhamnopyranose, the 6-O-methyl-beta-D-glucopyranosyl-(1 leads to 4)-2,3-di-O-methyl-alpha- L-rhamnopyranose, and the beta-D-glucopyranosyl-(1 leads to 4)-2,3-di-O-methyl-alpha- L-rhamnopyranose disaccharides were synthesized and characterized, and their activities were examined. Only the phenolic glycolipids containing 3,6-di-O-methyl-beta-D-glucopyranosyl at the nonreducing terminus were efficient in binding the anti-glycolipid immunoglobulin M, and the 3,6-di-O-methyl-beta-D-glucopyranosyl-containing di- and trisaccharides were the most effective in inhibiting this binding. Thus, the 3,6-di-O-methyl-beta-D-glucopyranosyl substituent was recognized as the primary antigen determinant in phenolic glycolipid I. With this information, bovine serum albumin containing reductively aminated 3,6-di-O-methyl-beta-D-glucopyranosyl-(1 leads to 4)-2,3-di-O-methyl- L-rhamnose was prepared and shown to be highly active in the serodiagnosis of leprosy.

Antigens, Bacterial↗
PubMed1986

Identification of Schistosoma mansoni glycolipids that share immunogenic carbohydrate epitopes with glycoproteins.

The immunoreactivity of sera of infected hosts against glycolipids derived from Schistosoma mansoni eggs, adult male worms, and cercariae was analyzed by immunostaining of glycolipids resolved by high-performance thin-layer chromatography. Eggs contained the greatest number of immunogenic glycolipids and bound the largest proportion of serum antibodies. Virtually all of the immunogenic egg glycolipids were neutrally charged and contained oligosaccharide chains larger in size than five sugar residues. The glycolipids of each developmental stage were shown by use of five monoclonal antibodies to share schistosome-specific carbohydrate epitopes that were also present on glycoproteins. Several of the carbohydrate epitopes were expressed throughout the life cycle, yet the overall structures of the glycolipids were not conserved. Quantitative analyses by solid-phase binding assays indicated that the carbohydrate epitopes were differentially expressed between the glycolipids and glycoproteins of developmental stages. Sera from infected humans and mice both contained very high levels of anti-carbohydrate antibodies that were reactive with the glycolipids, irrespective of the stage or intensity of disease. Mice harboring unisexual infections of either male or female worms also recognized the egg glycolipids in a pattern indistinguishable from that of patently infected mice. A greater proportion of the humoral response against egg antigens in infected humans was directed against protein determinants, as compared with infected mice.

Animals↗
PubMed1987

Characterization of glycolipids from the gastric cancer of a patient of p,O,Le(a-,b+) blood type: presence of incompatible blood group antigens in tumor tissues.

The antigens present in a gastric tumor obtained from a patient of blood group p,O,Le(a-,b+) were studied. The neutral glycolipids were isolated from the cancer tissues and characterized chemically and immunologically. The glycolipid pattern of the tumor was similar to that of the surrounding uninvolved mucosae. The major neutral glycolipids were found to be glucosylceramide, galactosylceramide, lactosylceramide, and the lacto series glycolipids, including the H, Lea, and Leb active fucolipids. The cancer tissues and the uninvolved mucosae did not contain galabiosylceramide, globotriaosylceramide, or globotetraosylceramide after separations by both thin layer chromatography and gas-liquid chromatography. Thin layer chromatography immunostaining was performed to detect incompatible blood group antigens. Immunostaining revealed the presence of globotriaosylceramide, globotetraosylceramide, Forssman glycolipid, and A active glycolipids in the cancer tissues. These incompatible blood group active glycolipids were absent from the uninvolved mucosae. The results indicate that the cancer tissues possess the ability to produce the globo series of glycolipids and the A active antigens but that the surrounding uninvolved mucosae could not synthesize these glycolipids.

Aged↗
PubMed1984

Glycolipid antigens with blood group I and i specificities from human adult and umbilical cord erythrocytes.

Neutral glycolipids and gangliosides of umbilical cord and adult human erythrocytes were separated by high performance liquid chromatography, and each fraction was analyzed by direct binding of anti-I (Ma) and anti-i (Den) on solid phase glycolipid-lecithin-cholesterol. The I- and i-active glycolipids were isolated and their structures were determined by methylation analysis and direct probe mass spectrometry. The major I antigen in adult erythrocytes, showing a remarkable binding activity with anti-I(Ma), was found in one neutral glycolipid fraction, designated fraction y4, which was identified as a mixture of two glycolipids of a new type, lactoisooctaosylceramide and monofucosyllactoisooctaosylceramide (for structures, see Table I). In addition, two gangliosides displaying direct binding activity with anti-I(Ma) were identified as monosialoganglioside G8, as previously described and disialosyllactoisooctaosylceramide, which showed the same level of I activity as the y4 glycolipid. The same ganglioside was recently isolated and characterized by Kundu and co-workers. The major i-active glycolipid antigen in umbilical cord erythrocytes, showing a strong binding activity with anti-i(Den), was a neutral glycolipid, x4a, which was identified as lactonorhexaosylceramide. This glycolipid without fucosyl or sialosyl substitution has not been isolated previously and was present as an obvious normal component of umbilical cord erythrocytes, but an extremely minor component of adult erythrocytes. Sialosyllactonorhexaosylceramide (G6) was isolated and characterized as a second i antigen of umbilical cord erythrocytes, but showed a very weak binding activity with the anti-i antibody. Although these sialosyl derivatives displayed only weak activity, the chemical quantity of the sialosyl derivatives is significantly large in fetal erythrocytes; therefore, Ii activity of human erythrocytes, in general, must be significantly dependent on sialosyl derivatives in addition to unsubstituted structures.

Adult↗
PubMed1971

Production and Properties of Antisera to Membrane Glycolipids of Mycoplasma pneumoniae.

The glycolipid haptens of Mycoplasma pneumoniae became immunogenic when bound to membrane proteins of Acholeplasma laidlawii by reaggregation. This process consisted of the solubilization of lipid-depleted A. laidlawii membranes and M. pneumoniae glycolipids in 20 mm sodium dodecyl sulfate and dialysis of the mixed solutions against 20 mm Mg(2+). The antibodies produced in rabbits to the reaggregated glycolipids inhibited the metabolism of M. pneumoniae, fixed complement with M. pneumoniae glycolipids or whole cells, precipitated M. pneumoniae glycolipids, and agglutinated M. pneumoniae cells. All these antibody activities could be blocked or absorbed by the purified glycolipids but not by a series of carbohydrates containing glucose and galactose. It was concluded that the antiserum to the reaggregated glycolipids may be regarded as a specific serum to membrane glycolipids of M. pneumoniae, since the antibodies to A. laidlawii membrane proteins, present in this serum, did not react with the glycolipids or with any other cell component of M. pneumoniae.

Journal Article↗
PubMed1983

Glycolipid-lectin interactions: detection by direct binding of 125I-lectins to thin layer chromatograms.

Glycolipids that bind 125I-labeled lectins are detected by autoradiography after thin layer chromatography of glycolipid standards or crude lipid extracts. Soybean agglutinin, Bandeiraea simplicifolia I isolectins A4 and B4, and Helix pomatia lectin are used to detect corresponding cell surface, glycolipid receptors in human and bovine erythrocytes. When lipid extracts from A and AB erythrocyte stroma are analyzed with Helix pomatia lectin, a polymorphic expression of blood group A glycolipid determinants is detected. The Bandeiraea simplicifolia isolectins react weakly with human erythrocyte glycolipids but bind at least 4 glycolipids in bovine stroma extracts. Soybean agglutinin reacts with glycolipids in all erythrocytes analyzed. This technique extends lectin specificity studies from inhibition analyses in aqueous systems using available, known structures to identification of specific, lectin-binding glycolipids in crude lipid extracts of cell membranes.

ABO Blood-Group System↗
PubMed1991

Search for antibodies to neutral glycolipids in sera of patients with Guillain-Barré syndrome.

Sera from 54 patients with Guillain-Barré syndrome (GBS), 34 patients with other neurological diseases (OND) and 32 healthy controls were tested for antibodies to total lipid fractions and higher neutral glycolipid fractions isolated from human and dog nerves, purified Forssman glycolipid and a panel of purified neutral glycolipids by both an enzyme-linked immunosorbent assay (ELISA) and a thin-layer chromatogram (TLC)-overlay technique. IgM and IgG antibodies to total lipid fractions, as well as to galactocerebroside, ceramide dihexoside, ceramide trihexoside, and globoside were not significantly elevated in the sera of GBS patients as compared to controls. High levels of anti-asialo-GM1 IgG antibodies, however, were detected in 6 of 54 (11%) GBS patients and 1 of 30 (3%) OND patients. Intense reactivity with purified Forssman glycolipid and a number of glycolipid antigens in higher neutral glycolipid enriched fractions of human cauda equina and dog sciatic nerves was noted by TLC-immunostaining in many GBS and control sera. Although the levels of anti-Forssman IgM were significantly decreased in GBS sera compared with normal sera (P less than 0.05) and OND sera (P less than 0.02), the levels of anti-Forssman IgG antibodies were not significantly different. With the possible exception of IgG antibodies to asialo-GM1, our results suggest that serum antibodies against Forssman glycolipid and neutral glycolipids are not significantly elevated in GBS patients and, thus, are unlikely to play an important role in the pathogenesis of this disease.

Animals↗
PubMed1992

Antibodies to acidic glycolipids in Guillain-Barré syndrome and chronic inflammatory demyelinating polyneuropathy.

Using an enzyme-linked immunosorbent assay and a thin-layer chromatography-immunostaining procedure, we detected serum antibodies against acidic glycolipids in 36 of 53 patients with Guillain-Barré syndrome (GBS) and 8 of 16 patients with chronic inflammatory demyelinating polyneuropathy (CIDP). Although we also found anti-acidic glycolipid antibodies in 4 of 13 patients with other neurological diseases; 2 of 10 patients with multiple sclerosis; 8 of 33 patients with inflammatory, infectious, allergic or autoimmune disorders and 3 of 32 healthy subjects, the levels of antibodies in these controls were much lower than in GBS patients. There were several patterns of reactivity of GBS sera including antibodies to LM1 and HexLM1, GM1 or GD1b or both, various other gangliosides, sulfated glycolipids, and as yet unidentified glycolipids. Sera from 30% of GBS patients had antibodies against two or more antigenically distinct acidic glycolipid antigens. Levels of anti-acidic glycolipid antibodies correlated with clinical symptoms in 9 of 11 GBS patients. While the increased incidence of antibodies to acidic glycolipids in patients with GBS (P less than 0.001) and CIDP (P less than 0.025) compared to controls could be an epiphenomenon, anti-acidic glycolipid antibodies may play a role in nerve injury in some GBS and CIDP patients.

Carbohydrate Sequence↗
PubMed1995

Production of human monoclonal antibodies to i blood group by EBV-induced transformation: possible presence of a new glycolipid in cord red cell membranes and human hematopoietic cell lines.

To study the differentiation-associated glycolipid two anti-i mAb producers, GL-1 and GL-2, were established from the combination of EBV-induced transformation of normal PBL and immune lysis of fluorescent dye-trapped liposome-containing bovine i-active glycolipid. The mAb GL-1 reacted with both sialosylparagloboside and pentahexosyl ceramide and the bovine i-active glycolipid whereas mAb GL-2 reacted only with the bovine i-active glycolipid in LILA. Both mAbs cold-agglutinate human cord red cells but not adult red cells. However, unexpectedly, the majority of the reactivity of these mAbs in human cord red cells on TLC was not identical to the i-active glycolipid. The GL-1 antigenic substance is considered to be a glycolipid distinct from the i-active glycolipid because the immunoreactivity was canceled with endoglycoceramidase which cleaves a linkage between the oligosaccharide and ceramide. Based on complement cytolysis with the mAb, 15 hematopoietic cell lines and normal peripheral lymphocytes were screened for susceptibility to the mAbs. A Burkitt lymphoma cell line, Ramos, was most sensitive among those tested, and BJA-B, Daudi, Namalwa in the B cell lines, TALL-1, Jurkatt in the T-cell lines and HL-60 in the non-lymphoid cell lines were sensitive whereas normal lymphocytes or other 8 cell lines were not. An immunoreactive spot with the same Rf with cord red cells was also detected in sensitive cell lines. The possible presence of a new glycolipid antigen determined from the mAb and related to the differentiation of hematopoietic cells was speculated.

Antibodies, Monoclonal↗
PubMed1982

Membrane-associated, fucose-containing glycoproteins and glycolipids of cultured epithelial cells from human colonic adenocarcinoma and fetal intestine.

Fucose-containing glycoproteins and glycolipids were compared in three human colon cancer cell lines and five human fetal intestinal epithelial cell lines. Cells were labeled by culturing cells in the presence of L-[3H]-fucose. Fucose was incorporated into both the membrane and cytoplasmic fractions of all three colon cancer cell lines to a much lesser extent than into fetal cells. When the relative fucose labeling of glycolipids and glycoproteins were examined, a much greater proportion of fucose labeling in the membrane was associated with lipid in colon cancer cells (11.6-16.7%) compared to fetal intestinal cells (1.3-2.5%). Fluorographic analysis of SDS-polyacrylamide gel electrophoresis of fucose-labeled glycoproteins revealed a rather uniform labeling pattern of fetal intestinal cells which was distinct from those of colon cancer cells. Thin-layer chromatographic analysis of fucose labeled glycolipids of all three colon cancer cell lines indicated the presence of fucose-containing glycolipids with carbohydrate chain lengths greater than five sugars. Glycolipids of the SKCO-1 cells in particular appear to consist predominantly of complex fucose-containing glycolipids. These results indicate that significant qualitative differences in the fucose-containing glycoproteins and glycolipids exist between the membranes of human colon cancer cells and fetal intestinal cells and that complex fuco-glycolipids with long carbohydrate side chains are present in the three human colon cancer cell lines.

Adenocarcinoma↗
PubMed2004

Binding of Bifidobacterium bifidum and Lactobacillus reuteri to the carbohydrate moieties of intestinal glycolipids recognized by peanut agglutinin.

We examined binding of Bifidobacterium bifidum and Lactobacillus reuteri to the carbohydrate moieties of glycolipids extracted from human enterocyte-like Caco-2 cells in this study. In binding assays to reference glycolipids of different carbohydrate compositions, B. bifidum EB102 bound strongly to gangliotetraosylceramide (asialo-GM1) and less strongly to gangliotriaosylceramide (asialo-GM2), lactosylceramide and sulfatide. The binding profile of B. bifidum EB102 was almost identical to that of L. reuteri JCM1081 described previously [Lett. Appl. Microbiol. 27 (1998) 130]. When we examined binding to neutral glycolipids extracted from Caco-2 cells, the binding profiles of B. bifidum EB102 and L. reuteri JCM1081 were very similar to that shown by peanut agglutinin (PNA). Binding of both strains to periodate-treated intestinal glycolipids was completely abolished, suggesting that the bacterial cells bind to carbohydrate moieties of the glycolipids. Furthermore, B. bifidum EB102 was found to express multiple glycolipid-binding proteinaceaous components on the cell surface. These results strongly suggested involvement of cell-surface proteinaceous components of B. bifidum in binding to the carbohydrate moieties of intestinal glycolipids recognized by PNA. Binding ability of B. bifidum and L. reuteri to intestinal glycolipids may play a crucial role for colonization on the mucosal surface of the intestine.

Bifidobacterium↗
PubMed1996

Glycolipids of human primary testicular germ cell tumours.

The glycolipid content of human non-seminomatous germ cell tumour cell lines correlates with their differentiation lineage. To analyse whether this reflects the situation in primary tumours, we studied five embryonal carcinomas, five yolk sac tumours and nine (mixed) non-seminomas, using thin-layer chromatography and carbohydrate immunostaining. We also analysed the glycolipid content of 19 seminomas to reveal their relationship with non-seminomas. Lactosylceramide (CDH) was detected in all embryonal carcinomas, but in fewer than half of the seminomas. Seminomas and embryonal carcinomas contained globoseries glycolipids, including globotriosylceramide (Gb3), globoside (Gb4), galactosy globoside (Gb5) and sialy1 galactosyl globoside (GL7). The lacto-series glycolipid Le(x) was found in all embryonal carcinomas, but only in one seminoma. Gangliosides GD3 and GT3 were detected in many seminomas, but rarely in embryonal carcinomas. Yolk sac tumours displayed a heterogeneous glycolipid profile. Compared with seminomas and pure embryonal carcinomas, differentiated non-seminomas had reduced levels of globo-series glycolipids, especially Gb3 and Gb5, whereas CDH, Le(x), GD3 and GT3 were found in the majority of cases. Thus, the glycolipid content of non-seminoma cell lines reflects the situation in primary tumours. Globo-series glycolipids are similarly expressed in seminomas and embryonal carcinomas. The expression of Gb3 and Gb5 is reduced in non-seminomas upon differentiation. Le(x) expression in non-seminomas, including embryonal carcinomas, allows discrimination from seminomas. Expression of gangliosides in seminomas might indicate their maturation from ganglioside-negative precursor cells. Reprogramming of these precursors would result in the formation of Le(x)-expressing embryonal carcinomas.

Carbohydrate Sequence↗
PubMed1966

The isolation and partial characterization of glycolipids of normal human leucocytes.

1. The lipids of purified human leucocytes were extracted with chloroform-methanol and the extract was washed with water. Glycolipids, isolated by Florisil chromatography, were subjected to mild alkaline hydrolysis and the alkali-resistant fraction was fractionated on a silicic acid column. 2. Three classes of glycolipid were separated. The less polar, containing 3.6% of the total glycolipid hexose as galactose, was tentatively identified as ceramide monohexoside. The major glycolipid fraction was characterized as ceramide dihexosides. The more polar glycolipids comprised 1.6% of the total glycolipid hexose as galactose and glucose (in the molar ratio 2:1) and were non-acidic. This class was separated as a mixture containing ninhydrin-positive glycolipids. 3. The ceramide dihexosides taken from two leucocyte preparations accounted for 15.2% and 16.4% by weight of the total lipids. 4. The carbohydrate moiety of the ceramide dihexosides contained galactose and glucose in the molar ratio 2:1. Partial acid hydrolysis and paper chromatography indicated that the hexoses are present as disaccharides, lactose being identified as one of them. 5. Palmitic acid (C(16:0)) and nervonic acid (C(24:1)) were the major fatty acids of this glycolipid. Hydroxy fatty acids were not detected.

Chemical Phenomena↗
PubMed2002

Inhibition of glycolipid shedding rescues recognition of a CD1+ T cell lymphoma by natural killer T (NKT) cells.

Neoplastic transformation of cells is accompanied by an aberration of cell surface glycolipid composition. These tumor-associated, altered glycosphingolipids are often shed into the tumor cell microenvironment and mediate immunosuppressive activity. The nature and form of glycolipids shed by a variety of tumor cell lines and the mechanism(s) of shedding have been well characterized. The murine T cell lymphoma line, L5178Y-R, is known to shed a tumor-associated glycolipid, gangliotriaosylceramide, into the culture medium. We analyzed the effect of glycolipids from L5178Y-R on antigen presentation by murine CD1d1 molecules. CD1d1 molecules present glycolipid antigens to a specialized class of T cells called natural killer T (NKT) cells that mainly express a T cell receptor alpha chain (Valpha14Jalpha281) associated with Vbeta chains of limited diversity. In the current report, we found that L5178Y-R cells express CD1 on their cell surface yet are unable to stimulate CD1d1-specific NKT cells. We hypothesized that the glycolipid(s) shed by L5178Y-R inhibited antigen presentation by CD1d1. Pretreatment of CD1d1(+) cells with conditioned medium from L5178Y-R inhibited CD1-specific stimulation of canonical (Valpha14(+)) but not noncanonical (Valpha5(+)) NKT cells. Exogenous addition of lipids extracted from L5178Y-R cells as well as purified gangliotriaosylceramide mimicked this effect. Inhibition of glycolipid shedding in L5178Y-R cells with d-1-phenyl-2-hexadecanoylamino-3-morpholino-1-propanol resulted in the rescue of CD1d1 recognition by canonical (but not noncanonical) NKT cells. These results suggest that one means by which certain tumor cells can evade the host's innate antitumor immune response is by shedding glycolipids that inhibit CD1-mediated antigen presentation to NKT cells.

Animals↗
PubMed1984

Gangliosides and neutral glycolipids in guinea pig adrenal glands.

Glycolipids were isolated from the adrenal glands of seven strains of guinea pig by DEAE-Sephadex and Iatrobeads column chromatographies. The average lipid-bound sialic acid content of the adrenal glands was estimated to be 96.0 +/- 30.4 nmol/g fresh tissue. The ganglioside fraction contained two major gangliosides which accounted for 82% of the total lipid-bound sialic acid. They were identified as N-acetylneuraminylgalactosylceramide (GM4) and N-acetylneuraminyllactosylceramide (GM3). The neutral glycolipid fraction contained one major and three minor glycolipids. The major glycolipid was identified as galactosylceramide, which accounted for 81% of the total glycolipid. The other three glycolipids were identified as Forssman glycolipid (7%), lactosylceramide (5%), and gangliotriaosylceramide (7%). In all strains examined, the glycolipid patterns were similar.

Adrenal Glands↗
PubMed1996

Structures of the glycolipid antigens of members of the third biovariant complex of Mycobacterium fortuitum.

Among the fast-growing mycobacteria, members of the Mycobacterium fortuitum complex are the most-commonly cited opportunistic human pathogens, notably in post-surgical infections. Previous studies showed that this complex was composed of four well-identified species and a group of isolates that did not correspond to recognized species, which has been referred to as the third biovariant complex. The occurrence and chemical structure of the glycolipid antigens of six strains that belong to this latter group were examined in the present study. Based on the TLC profiles, resistance to alkali and seroreactivities of their glycolipids, the examined strains were classified into three groups: one group was devoid of species-specific glycolipid and the two other groups contained alkali-stable or alkali-labile glycoconjugates. The structures of the major glycolipid antigens of the latter two groups were elucidated by fast-atom-bombardment MS, one-dimensional and two-dimensional NMR spectroscopy and conventional chemical analyses. The alkali-stable glycolipids were structurally identical to the C-mycoside-type glycopeptidolipids characterized in the taxonomically related species Mycobacterium peregrinum. The major alkali-labile glycolipid was identified as beta-Glcp-1 --> 6)-alpha-Glcp2Acyl-(1 --> 1)-alpha-GLcp3,4,6Acyl3. The acyl substituents consisted on one acetyl group and three fatty acyl residues composed mainly of tetradecanoyl residues, but significant amounts of 2-methylhexadecanoyl and 2-methyloctadecanoyl substituents were also present. The heterogeneity of the glycolipid content of members of the third biovariant complex of M. fortuitum demonstrated in the present study confirms the heterogeneity of the complex. In addition, the occurrence of a species-specific glycolipid in some strains supports the hypothesis that some strains of this complex of M. fortuitum may belong to a new mycobacterial species.

Antigens, Bacterial↗
PubMed1984

Generation and characterization of monoclonal antibodies to the phenolic glycolipid of Mycobacterium leprae.

Nine cloned cell lines producing antibodies to the unique phenolic glycolipid of Mycobacterium leprae have been established as a result of fusions with spleens from mice immunized with the glycolipid complexed with methylated bovine serum albumin. One of the antibodies was relatively nonspecific, binding to a related glycolipid from Mycobacterium kansasii, but the remaining antibodies were specific for the M. leprae lipid. Some of the antibodies required the intact (trisaccharide) carbohydrate portion for recognition of the glycolipid antigen, whereas others recognized partially hydrolyzed forms lacking one or two sugar residues. Monoclonal antibodies directed at the terminal saccharide of the glycolipid showed the greatest specificity for M. leprae in enzyme-linked immunoassays. These antibodies brightly labeled whole mycobacteria in indirect immunofluorescence experiments, demonstrating the surface location of M. leprae-specific determinants of the glycolipid antigen. In addition to their use in providing information about the antigenic properties of the phenolic glycolipid, these antibodies have potential applications for elucidating the roles of glycolipid in the pathogenesis of leprosy.

Animals↗