M protein and protein F act as important determinants of cell-specific tropism of Streptococcus pyogenes in skin tissue

The pathogenic gram-positive bacterium Streptococcus pyogenes (group A streptococcus) causes numerous diseases of cutaneous tissue, each of which is initiated after the interaction of the bacterium with the cells of the epidermis. In this study, we show that different surface proteins of S. pyogenes play important roles in determining the cell-specific tropism of the bacterium in skin. Using streptococcal strains with defined mutations in the genes which encode surface proteins in combination with primary cultures of human skin and an in situ adherence assay which uses histological sections of human skin, we show that the M protein of S. pyogenes mediates the binding of the bacterium to keratinocytes, while a second streptococcal surface protein, protein F, directs the adherence of the organism to Langerhans' cells. Characterization of binding revealed that adherence was inhibited by purified streptococcal proteins and pretreatment of both host cells with the protease trypsin. Adherence was only slightly affected by the state of keratinocyte differentiation in vitro, but was considerably modulated in response to environmental conditions known to regulate expression of M protein and protein F, suggesting that the interaction between these bacterial cell-surface structures/adhesins and keratinocytes and Langerhans' cells may play an important role in streptococcal skin disease.

Sequence changes in the pilus subunit lead to tropism variation of Neisseria gonorrhoeae to human tissue

Pili of Neisseria gonorrhoeae are correlated with increased bacterial attachment to epithelial cells and undergo both phase and antigenic variation. Phase variation of gonococcal pili can be brought about by recombination events in the pilin structural gene, pilE, or by the on/off switch in expression of PilC, a pilus biogenesis protein for which two loci exist. We have studied the binding to epithelial cell lines and to fixed tissue sections of N. gonorrhoeae MS11 derivatives and mutants carrying structurally defined PilE and PilC proteins. In situ binding studies of N. gonorrhoeae to formalin-fixed tissue sections resulted in a binding pattern similar to that obtained using viable epithelial cell lines of different origin. Piliated gonococcal clones, containing different pilE sequences, varied dramatically from one another in their efficiencies at binding to corneal and conjunctival tissue, but bound equally well to cervical and endometrial tissues. Further, the binding data suggested that PilC expression by itself, i.e. without pili, cannot confer bacterial binding and that expression of either PilC1 or PilC2 does not confer different binding properties to the bacterial cells. Possible receptors for piliated gonococci were expressed in human tissues, such as cervix, endometrium, cornea, intestine, stomach, mid-brain and meninges, but not in human kidney. Pretreatment of the target tissues with Proteinase K decreased the gonococcal binding dramatically, whereas pretreatment with neuraminidase and meta-periodate, which cleave carbon-carbon linkages between vicinal hydroxyl groups in carbohydrates, did not affect attachment of gonococci. These data argue that pilus-dependent attachment of N. gonorrhoeae to human tissue may be mediated by a eukaryotic receptor having protein characteristics, and that the pilus subunit sequence may play an important role in the interaction with human cornea.

Helicobacter pylori: molecular basis for host recognition and bacterial adherence

The bacterium Helicobacter pylori is tropic for epithelial cells and the mucus layer in the stomach lining, and is associated with the development of gastritis, ulcers and possibly also gastric malignancies. Adherence to the gastric epithelial cells is mediated by fucosylated blood-group antigens associated with blood-group O phenotype, which could explain the higher prevalence of ulcerative disease in individuals with this blood group.

Lectins are sensitive tools for defining the differentiation programs of mouse gut epithelial cell lineages

We have used histochemical methods to survey the cellular patterns of binding of a panel of 45 lectins with well-defined carbohydrate specificities to sections prepared from various regions of the gastric-to-colonic axis of fetal, neonatal, and adult FVB/N mouse gut. The results suggest that lectins can be used as remarkably sensitive tools to describe the differentiation programs of gastric and intestinal epithelial cell lineages as a function of their position along the cephalocaudal axis of the gut and as a function of developmental stage. Studies of intestinal isografts and transgenic mice that express Simian virus-40 T antigen in enterocytes suggest that many of these cell lineage-specific and spatial patterns of glycoconjugate production can be established and maintained in the absence of exposure to luminal contents and in the presence of specific proliferative abnormalities. This lectin panel should be useful for operationally defining subpopulations of the principal gut epithelial cell lineages in normal strains of mice, for describing variations in gut epithelial cell differentiation programs in mutant and transgenic mice, and for recovering specific epithelial cell lineages or subpopulations.

Attachment of Helicobacter pylori to human gastric epithelium mediated by blood group antigens

Helicobacter pylori is associated with development of gastritis, gastric ulcers, and adenocarcinomas in humans. The Lewis(b) (Le(b)) blood group antigen mediates H. pylori attachment to human gastric mucosa. Soluble glycoproteins presenting the Leb antigen or antibodies to the Leb antigen inhibited bacterial binding. Gastric tissue lacking Leb expression did not bind H. pylori. Bacteria did not bind to Leb antigen substituted with a terminal GalNAc alpha 1-3 residue (blood group A determinant), suggesting that the availability of H. pylori receptors might be reduced in individuals of blood group A and B phenotypes, as compared with blood group O individuals.

An in vitro adherence assay reveals that Helicobacter pylori exhibits cell lineage-specific tropism in the human gastric epithelium

Helicobacter pylori is a microaerophilic bacterium found in the stomach of asymptomatic humans as well as patients with acid peptic disease and gastric adenocarcinoma. We have developed an in situ adherence assay to examine the cell lineage-specific nature of binding of this organism and to characterize the nature of cell surface receptors that recognize its adhesin. Fluorescein isothiocyanate-labeled H. pylori strains were bound to surface mucous cells present in the pit region of human and rat gastric units but not to mucous neck, parietal, or chief cell lineages present in the glandular domains of these units. Binding was abolished by proteinase K treatment of tissue sections and by pretreatment of the bacteria with bovine submaxillary gland mucin, a rich source of fucosylated and sialylated carbohydrates. Several lines of evidence suggest that binding to surface mucous cells is not dependent upon terminal nonsubstituted alpha 2,3- and alpha 2,6-linked sialic acids in the adhesin receptor: (i) binding was not inhibited by incubating H. pylori strains with sialylated glycoconjugates such as fetuin and free sialyllactose; (ii) immunohistochemical stainings using the sialic acid-specific Sambucus nigra and Maackia amurensis lectins and the cholera toxin B subunit did not detect any sialylated glycoconjugates in these epithelial cells; and (iii) binding was not sensitive to metaperiodate under conditions that selectively cleaved carbons 8 and 9 of terminal nonmodified sialic acids. A role for fucosylated epitopes in the glycoprotein(s) that mediate binding of H. pylori to surface mucous cells was suggested by the facts that this lineage coexpresses the adhesin receptor and major fucosylated histo-blood group antigens, that monoclonal antibodies specific for histo-blood group antigens H, B, and Leb block binding, and that the lectin Ulex europaeus type 1 agglutinin, which is specific for alpha-L-fucose, also bound to the same cells that bound the bacteria. Furthermore, human colostrum secretory IgA inhibited adhesion in a metaperiodate- and alpha-L-fucosidase-sensitive but neuraminidase-independent fashion. The in situ adherence assay should be useful in further characterizing the H. pylori adhesin and its receptor and for identifying therapeutically useful compounds that inhibit strain-specific and cell lineage-specific binding of this human pathogen.

Paracrystalline inclusions of a novel ferritin containing nonheme iron, produced by the human gastric pathogen Helicobacter pylori: evidence for a third class of ferritins

An abundant 19.3-kDa Helicobacter pylori protein has been cloned, and the sequence is homologous with a ferritin-like protein produced by Escherichia coli K-12. Homologies are also present with a number of eucaryotic ferritins, as well as with the heme group-containing bacterioferritins. All amino acids involved in chelation of inorganic iron by ferritins from humans and other higher species are conserved in the H. pylori protein. Consistent with the structural data indicating an iron-binding function, E. coli overexpressing the H. pylori ferritin-like protein accumulates almost 10 times more nonheme iron than vector controls, and the iron-binding activity copurifies with the 19.3-kDa protein. Immunoelectron microscopy of H. pylori, as well as of E. coli overexpressing the H. pylori gene, demonstrates that the gene product has a cytoplasmic location where it forms paracrystalline inclusions. On the basis of these structural and functional data, we propose that the H. pylori gene product (termed Pfr) forms the basis for a second class of bacterial ferritins designed to store nonheme iron.

Deantigenation of human erythrocytes by bacterial glycosidases--evidence for the noninvolvement of medium-sized glycosphingolipids in the Dolichos biflorus lectin hemagglutination

Fresh human A1 erythrocytes, washed and pretreated in phosphate buffer with or without papain, were incubated at 37 degrees C with blood group-degrading enzymes from the human fecal Ruminococcus torques strain IX-70. The effects were assayed as changes in hemagglutination patterns, and blood group activities of alkali stable glycolipid extracts from the enzyme-treated cells using Dolichos biflorus anti-A1 lectin, Ulex europaeus type 1 anti-H lectin, and various monoclonal anti-A antibodies. Hemolysis was negligible (less than or equal to 1% after 6 h), and the osmotic fragility increased slightly only after papain treatment. The papain-untreated A1 erythrocytes lost D. biflorus agglutinability within minutes at room temperature with the unfractionated bacterial enzyme mixture IX-70 (42 mU 1,3-alpha-N-acetylgalactosaminidase (alpha-GalNAc'ase)/ml), but remained A active by strong agglutination with BioClone anti-A antibody even after 6 h of incubation. Thin layer chromatographic (TLC) immunostaining of extracted lipids showed hydrolysis of D. biflorus binding glycosphingolipids with more than six monosaccharides after 1 h, i.e., at a slower rate than the loss of D. biflorus agglutinability. Disappearance of these glycosphingolipids after 1 h paralleled the appearance of U. europaeus agglutinability and the strong binding of this lectin to glycolipid extracts in TLC immunoassays. A partly purified 1,3-alpha-GalNAc'ase (XI-117) (100 mU/ml) and a 1,2-alpha-fucosidase fraction (XI-50) containing alpha-GalNAc'ase (10 mU/ml) did not degrade blood group A active glycosphingolipids but completely abolished the D. biflorus agglutinability within 6 h. Papain pretreatment exposed U. europaeus receptors on the cell surface without changing the A1 hemagglutination pattern. It also facilitated a complete degradation of D. biflorus and U. europaeus reactive glycolipids with the IX-70 enzyme mixture within 6 h. The D. biflorus lectin was a good discriminator of A1/A2 subjects using erythrocyte lipid extracts but had a low affinity for the blood group A type 3 and type 4 glycosphingolipids in the TLC-overlay technique. In conclusion this study shows that (i) loss of D. biflorus A1 hemagglutination does not correlate with a loss of D. biflorus binding glycosphingolipids and (ii) loss of D. biflorus binding glycosphingolipids does not correlate with a loss of D. biflorus agglutinability. The results indicate that the serological D. biflorus agglutinability of A1 erythrocytes is not dependent on medium-sized glycosphingolipids (hexa- to dodecaglycosylceramides).

Enhancing effects of bile salts on the degradation of glycosphingolipids by glycosidases from bacteria of the human fecal flora

Different concentrations of ionic and non-ionic detergents were examined for optimization of the in vitro degradations of intestinal glycosphingolipids by alpha- and beta-glycosidases from human fecal bacteria. In 5 mM Triton X-100 the enzymes hydrolyzed glycosphingolipids with lactoseries type 1 and 2 chains essentially to lactosylceramide (LacCer). In 5 mM sodium di- and trihydroxy bile salts lactosylceramide was degraded to glycosylceramide (GlcCer) in varying extent by enzymes from all five strains. The minimal bile salt concentrations for optimal 1,4-beta-galactosidase activities varied between 1 and 20 mM, i.e., close to or above the critical micellar concentrations (cmc). Dihydroxy bile salts were the most efficient in promoting conversion of LacCer to GlcCer at concentrations below 10 mM and conjugation with a taurine residue did not markedly lower the GlcCer yield. The optimal detergent concentrations for hydrolyses of the p-nitrophenyl (pnp) glycosides Gal beta 1-pnp and GalNAc alpha 1-pnp were approximately 0.05 mM for Triton X-100 and 0.5 mM for sodium taurodeoxycholate, i.e., clearly below their reported cmc values. Galabiosylceramide, globotria- and globotetraosylceramides, not degraded in the Triton X-100 micelles, were also resistant to hydrolysis using the sodium bile salts as detergents. In contrast, lactotetraosylceramide and isoglobotriaosylceramide were significantly more degraded by enzymes from a Ruminococcus gnavus strain and gangliotetraosylceramide by enzymes from a Bifidobacterium bifidum and a Bifidobacterium infantis strain using bile salt detergents. All strains but R. gnavus released terminal GalNAc from para-Forssman but not from the globotetraosylceramide or Forssman structures using 5 mM sodium deoxycholate as detergent. GM1 desialylation by two Ruminococcus torques strains and the R. gnavus and B. bifidum strains were enhanced under identical conditions. We conclude that the observed effects on glycosphingolipid hydrolyses reflects variations in the micellar presentation of the substrates. In addition, detergents seem to have a direct stimulating effect on the glycosidases, however at concentrations 10-100-times below the ones optimal for glycolipid degradations. These results with optimized bile salt concentrations, further support our previous observations that these five fecal bacterial strains produce enzymes with selected specificities towards glycosphingolipid core chains of the lactoseries type 1 and 2.

The receptor repertoire defines the host range for attaching Escherichia coli strains that recognize globo-A

Escherichia coli strains which colonize the human urinary tract express lectins specific for different members of the globoseries of glycolipids, e.g., globotetraosylceramide and globo-A. This study investigated the importance of globo-A expression for attachment to human uroepithelial cells, colonization of the urinary tract, and severity of urinary tract infection. The expression of receptor-active glycolipids by erythrocytes and epithelial cells was analyzed by thin-layer chromatography and bacterial overlay as well as by bacterial binding to those cells. The epithelial expression of the globo-A receptor was restricted to individuals of blood group A with a positive secretor state. Consequently, globo-A binding E. coli strains attached only to epithelial cells from these individuals. In contrast, globoside-recognizing strains attached in similar numbers to uroepithelial cells regardless of the ABH blood group and secretor state of the donor. The role of host receptor expression for infection with globo-A-specific E. coli was analyzed in 1,473 children with urinary tract infections. All those infected with strains exclusively expressing globo-A-specific adhesins were found to be of blood group A, compared with 45% in the population at large (P less than 0.006). The inflammatory response (fever, C-reactive protein, erythrocyte sedimentation rate) of individuals infected with these strains was lower than that in individuals with infections caused by globoside binding strains. The results demonstrate the importance of fitness between host receptors and bacterial adhesins for infection and suggest that minor receptor epitope differences have profound effects on the disease process.

Bacteria of the human intestinal microbiota produce glycosidases specific for lacto-series glycosphingolipids

Five strains of human fecal bacteria, of the Ruminococcus and Bifidobacterium genera, produce extracellular alpha- and beta-glycosidases that degrade intestinal mucin oligosaccharides and glycosphingolipids of the lacto-series type 1 chain. We have tested the activities and substrate specificities of these enzymes using para-nitrophenyl glycosides and glycosphingolipids of different core chains (lacto, neolacto, globo, isoglobo, galabio, and ganglio), carrying different blood group determinants (A, H, X, Y, Forssman, and para-Forssman), and with different degrees of sialylation (mono- to tetra-sialo). Lactotetraosylceramide and neolactotetraosylceramide were the only core glycosphingolipids degraded by enzymes from these strains, resulting in lactosylceramide and glucosylceramide as the major end products. R. gnavus strain VI-268 did not degrade lactotetraosylceramide but only neolactotetraosylceramide yielding lactotriaosylceramide and lactosylceramide as the major end products. All strains but R. gnavus VI-268 also produced lactosylceramide from a bi-antennary 10-sugar glycosphingolipid with two blood group H determinants based on a lactotetraosylceramide core. Apart from strain specific blood group A-degrading (R. torques strain VIII-239 and IX-70, R. gnavus strain VI-268 and B. infantis VIII-240) and Forssman-degrading (R. torques VIII-239 and IX-70) activities, all strains also degraded the H-5, X-5, and Y-6 glycosphingolipids. All strains released N-acetylneuraminic acid from the gangliosides sialosyl-neolactotetraosylceramide, GD3, GD1a, GD1b, GT1b, and GQ1b corresponding to 2,3-alpha- and 2,8-alpha-N-acetylneuraminidase activities. The R. torques strains VIII-239 and IX-70 also partially desialylated GM1 to lactotetraosylceramide. The para-nitrophenyl glycoside degradations were often incompatible with the data from the glycosphingolipids degradations.(ABSTRACT TRUNCATED AT 250 WORDS)

Class II MHC antigens in the rat digestive system. Normal distribution and induced expression after interferon-gamma treatment in vivo

The normal and interferon-gamma induced expression of class II MHC antigens was investigated immunohistologically in the digestive system of LEW rats. In the normal state class II molecules were present in interstitial dendritic cells, B lymphocytes and epithelial cells. Epithelial class II expression was restricted to enterocytes in certain portions of the small intestine and to some duct epithelia in salivary glands. After continuous intravenous infusion of interferon-gamma (IFN-gamma) for 3 days, class II MHC antigens were induced in large vessel endothelium and in the surface epithelia of the tongue, oesophagus and proventricle. In the gastric glands class II molecules appeared in mucous neck cells and in parietal cells, while adjacent mucous surface cells and chief cells did not acquire class II reactivity. All enterocytes, including the previously negative colonic epithelium, were induced to express class II antigens. In the salivary glands class II antigens appeared in all duct epithelia. Serous acinar cells were induced in the parotids, but in the submandibular glands and in the pancreas the serous gland epithelium stayed negative. Our study thus shows that the effects of IFN-gamma on class II MHC antigen expression in vivo depend on the differentiation pathway of the individual cell. The normal distribution in rats suggest that class II MHC antigens may play a role in peptide transport across specialized epithelia. It remains to be determined whether such a function is enhanced after IFN treatment.

Binding specificities of wild-type and cloned Escherichia coli strains that recognize globo-A

In this study we compared the specificity for the globoseries of glycolipids of Escherichia coli expressing the O-negative, A-positive (ONAP) adhesin and clones transformed with the pap-like (prs or pap-2) gene cluster. Receptor-active glycolipids were identified by the ability of radiolabeled bacteria to bind to the glycolipids on thin-layer chromatogram plates. The ONAP adhesin and pap-like clones bound with high affinity to the globo-A and Forssman glycolipids. The ONAP strains did not recognize other glycolipids of the globoseries. In contrast, the pap-like clones also showed weak binding to globotriaosylceramide and reacted weakly with Gal alpha 1----4 Gal beta-latex beads. We suggest that the pap-like and ONAP adhesins recognize an epitope shared by the globo-A and Forssman structures, e.g., terminal GalNAc alpha 1----3 bound to Gal alpha 1----4Gal beta-containing glycolipids.

Intestinal sphingolipid excretion associated with feeding of phytohemagglutinin lectin (Phaseolus vulgaris) to germ-free and conventional rats

Intestinal sphingolipids of feces of germ-free and conventional rats were analyzed during the pair feeding of a complete defined diet containing phytohemagglutinin lectin (PHA) from red kidney beans (Phaseolus vulgaris) as 1% dietary protein in comparison to casein fed controls. Phytohemagglutinin in the diet increased the total fecal excretion of sphingomyelins (18-fold for germ-free and 20-fold for conventional rats), of non-acid glycosphingolipids (3.5-fold for germ-free and 9-fold for conventional rats) and also of the gangliosides (2.5-fold) for the germ-free rats compared to controls. For germ-free rats the increase of non-acid glycolipids was ascribed to an effect of the lectin strictly on the small intestinal mucosa, while for conventional rats an effect was seen also on the large intestinal mucosa. Increase of fecal gangliosides of germ-free rats was due mainly to an increased excretion of N-acetylneuraminosyl-lactosylceramide, a ganglioside species restricted to epithelial cells of duodenum, of upper jejunum and of large intestines. The effects on glycolipid excretion observed in germ-free rats and the rather similar effects seen in conventional animals suggested that the influence of dietary PHA was due directly to effects elicited by PHA binding to the enterocyte brush border membrane and not to secondary effects induced by increase in the luminal microflora.

Globo-A--a new receptor specificity for attaching Escherichia coli

Uropathogenic Escherichia coli strains designated as ONAP, based on their O negative A positive agglutination of human P1 erythrocytes, were shown to prefer the globo-A glycolipid as a receptor structure. The dependence on both the A terminal and the globoseries chain was confirmed by agglutination of human AP1, but not Ap or OP1 erythrocytes and by binding to the globo-A glycolipid on TLC plates. Neither Gal alpha 1----4Gal beta nor the A trisaccharide GalNAc alpha 1----3(Fuc alpha 1----2)Gal beta alone functioned as receptors. The bacteria thus appeared to recognize an epitope resulting from the combination of the terminal and internal structures.

Degradation of human intestinal glycosphingolipids by extracellular glycosidases from mucin-degrading bacteria of the human fecal flora

Certain normal strains of human fecal bacteria are unique in producing extracellular glycosidases that degrade the oligosaccharide chains of gut mucin glycoproteins. We have studied the action of such glycosidases partially purified from the cell-free supernates of five of these strains on intestinal glycosphingolipids isolated from human meconium. The glycolipids were sialosyl-lactosylceramide, lactosylceramide, and fucolipids with A, B, H, Lea, or Leb blood group determinants. In addition to the strain-specific high blood group A-degrading activities (Ruminococcus torques strains VIII-239 and IX-70), B-degrading activity (Ruminococcus AB strain VI-268), and H-degrading activities (all strains) corresponding to alpha 1-3-N-acetylgalactosaminidase, alpha 1-3-galactosidase and alpha 1-2-fucosidase, respectively, all strains also degraded sialosyl-lactosylceramide and Lea and Leb antigenic glycolipids, indicating the presence of alpha 2-3-neuraminidases and alpha 1-4-fucosidases. Enzyme preparations from Bifidobacterium infantis strain VIII-240 and R. torques strain VIII-239 hydrolyzed the Lea active glycolipid directly to lactosylceramide, suggesting the presence of endo-beta 1-3-N-acetylglucosaminidase activities. Similar endo-beta-N-acetylglucosaminidase activities were identified in four of the five enzyme preparations. The enzymes produced by R. AB strain VI-268 lacked this activity as well as beta 1-3-galactosidase, and thus degradation stopped at lactotetraosylceramide. With enzyme preparations from the other strains lactosylceramide was the single major degradation product from complex glycosphingolipids with less than 30% further degradation to glucosylceramide within 48 h. We conclude that glycosidases from mucin-degrading strains of human enteric bacteria degrade oligosaccharide chains of lactoseries fucolipids and gangliosides of intestinal origin primarily to lactosylceramide. Since several genera of enteric bacteria bind preferentially to lactosylceramide in vitro, mucin-degrading strains may have an important ecological role in host-microbial associations in the human gut.

Interferon-gamma in vivo. Induction and loss of class II MHC antigens and immature myelomonocytic cells in rat organs

The effects of recombinant rat interferon-gamma on class II major histocompatibility complex antigen expression in vivo were studied by immunohistology in LEW rats after continuous intravenous infusion for three days. Interferon-gamma administration led to a systemic induction of class II molecules in previously negative parenchymal and stromal cells. The induction patterns observed were highly reproducible, but not closely dose dependent within a 25-fold dose difference tested. However, the effect of interferon infusion differed profoundly in individual cell types, and appeared to be related to the differentiation stage of each cell population. Thus, epithelial cells like duct epithelia, urothelium or basal ear skin keratinocytes as well as endothelia in big vessels were strongly and easily induced for class II antigen expression. Parenchymal cells like cardiomyocytes and hepatocytes showed intermediate reactivity, while capillary endothelia, neurons in the brain, straight proximal kidney tubules or endocrine pancreatic islet cells did not express class II antigens. The induced expression was rapidly lost from most cells within one or two days after interferon withdrawal; the only exception occurred in keratinocytes. Long-term alterations were, however, still found 14 days after infusion. Interstitial class II-positive dendritic-shaped cells were increased in the organs and hepatic Kupffer cells carried class II antigens. On conventional histology all organs appeared perfectly normal at this date. After three days of interferon, cells of an immature myelomonocytic phenotype occluded medium-sized and small veins in all organs and occurred in granuloma-like lesions in the liver. Although these cells quickly disappeared after interferon withdrawal they might have been at least partially responsible for single deaths on day three. Our study provides a basis for testing the immunological in vivo function of parenchymal class II antigen expression and its differentiation-specific regulation.

The mono- and difucosyl blood group B glycosphingolipids of rat large intestine differ in type of core saccharide

Two blood group B-active glycosphingolipids were isolated from rat large intestine and characterized by mass spectrometry, proton NMR spectroscopy and methylation analysis. The following structures were concluded: Gal alpha 1----3(Fuc alpha 1----2)Gal beta 1----3GlcNAc beta 1----3Gal beta 1----4Glc beta 1----1Cer and Gal alpha 1----3(Fuc alpha 1----2)Gal beta 1----4(Fuc alpha 1----3)GlcNAc beta 1----3Gal beta 1----4Glc beta 1----1Cer. The two glycolipids thus differ in their core saccharides (type 1 and type 2 chain, respectively) and therefore must have different pathways for biosynthesis.

Fecal excretion of intestinal glycosphingolipids by newborns and young children

Glycosphingolipids were shown to persist in human fecal excretions from birth up 2 years of age. The pattern of glycosphingolipids was dependent on blood group and secretor status of the child and changed dramatically during the first months of life. Perinatally cerebroside, hematoside and blood group active fucolipids were dominating among fecal glycolipids. From the time of weaning lactosylceramide abruptly became and then persisted as a dominating glycolipid although cerebroside, complex gangliosides and blood group active fucolipids could still be detected in feces even at 2 years of age.

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

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