A quantitative analysis of cell surface glycosphingolipid with a fluorescence activated cell sorter

Biochemical characterization of the feline AB blood group system

The biochemical nature of the feline AB blood group system was characterized by analysing red blood cells from homozygous (genotype A/A) and heterozygous (A/B) type A, type B (B/B), and type AB cats. High performance thin layer chromatography (HPTLC) of red cell glycolipids revealed that specific neuraminic acids (NA) on gangliosides, containing ceramide dihexoside (CDH) as a backbone, correlated with the feline AB blood group antigens. Although disialogangliosides predominated, mono- and trisialogangliosides were also isolated. B cats expressed solely N-acetyl-NA (NeuNAc) on these gangliosides. In addition to expressing N-glycolyl-NA (NeuNGc) containing gangliosides, A red cells have gangliosides with only NeuNAc or mixtures of both NA. HPTLC profiles of disialogangliosides from homozygous and heterozygous A cats differed slightly in the quantity of disialogangliosides. Equal amounts of NeuNAc and NeuNGc containing disialogangliosides, as well as two intermediary forms, were recovered from AB erythrocytes. Analysing disialogangliosides from red cells belonging to 17 genetically related cats, we consistently obtained the expected disialoganglioside profile, based on blood typing and pedigree information. SDS-PAGE of red cell membrane proteins and blotting with Triticum vulgaris, a lectin recognizing NeuNAc, revealed glycoproteins of approximately 51, 53, and 80 kD in B and AB cats but only a faint band of approximately 53 kD in A cats. By haemagglutination, Triticum vulgaris could also distinguish different blood types by specifically binding to B and AB cells.(ABSTRACT TRUNCATED AT 250 WORDS)

Concanavalin A-stimulated expression of gangliosides with GalNAc beta 1-4(NeuAc alpha 2-3)Gal beta structure in murine thymocytes

We analysed the glycolipids of mouse thymocytes before and after Concanavalin A (Con A) or recombinant interleukin-2 (rIL-2) stimulation by TLC-immunostaining with carbohydrate-specific antiglycolipid antibodies. The thymocytes were cultured in serum-free medium in the presence of 500 ng ml-1 Con A, 10 U ml-1 rIL-2 or Con A plus rIL-2 for 6, 12, 24, 48, and 72 h, and were found to start proliferating 24 h after cultivation in the presence of Con A or Con A plus rIL-2, the maximum levels being reached at 72 h and 48 h, respectively, in a thymidine uptake experiment. The concentrations of II3Neu-Gg4Cer, Gg4Cer and IV3GalNAc alpha-Gb4Cer after 48 h Con A stimulation were found to be at almost the original levels. Conversely, II3Neu-Gg3Cer, which was not detected in the thymocytes at the start, began to appear after 48 h stimulation with Con A and Con A plus rIL-2, and IV3Neu-Gg5Cer in the cells 48 h after stimulation with Con A and Con A plus rIL-2 has increased to 41 and 44 times higher than in the original cells, respectively, as judged on TLC-immunostaining with monoclonal antibody YHD-06, which detects the GalNAc beta 1-4(NeuAc or NeuGc alpha 2-3)Gal beta-structure. These results indicate that the increased synthesis of both gangliosides, in other words, the activation of N-acetylgalactosaminyltransferase, is associated with the mitogen-induced proliferation.(ABSTRACT TRUNCATED AT 250 WORDS)

Preferential reactivity of autoantibodies in murine lupus NZB mice to neuraminidase-treated monosialogangliosides on B cells of mouse spleen

When analyzed by flow cytometry, reactivity of IgM autoantibodies in sera from NZB mice to spleen B cells, but not to T cells, from BALB/c mice was remarkably increased after treatment of the cells with Vibrio cholerae neuraminidase. By TLC immunostaining with the antibodies, neither neutral nor acidic glycosphingolipids from both BALB/c and NZB mouse spleens were found to be reactive, but after neuraminidase treatment of the TLC plate, prior to the immunostaining, three components became reactive. All of the reactive glycosphingolipids were found to carry a single sialic acid residue and were at a concentration less than 1.3% of the total lipid-bound sialic acids. Their mobilities on TLC plate were close to those of IV3 NeuAcnLc4Cer, IV3 NeuAcII3 NeuAcGg4Cer, and IV3 NeuAcII3 NeuAc2Gg4Cer. In addition, the monosialogangliosides, which became reactive with the autoantibodies after neuraminidase treatment, were found to be predominantly distributed on B cells from BALB/c mice spleen, but not on T cells by TLC immunostaining. These studies demonstrate that the majority of IgM autoantibodies to spleen lymphocytes in sera from NZB mice might react preferentially to terminal sugar residues of three new glycosphingolipids masked by a single sialic acid on B cells, but not on T cells.

Cryoprecipitation of an anti-Pr2 monoclonal IgM cold agglutinin in the presence of GM3 ganglioside

The mechanism of cryoprecipitation of a monoclonal IgM kappa cryoglobulin (Mou) with a cold agglutinin activity of Pr2 specificity has been studied. By immunodiffusion this cryoglobulin reacted (by its Fab' fragment) with micellar GM3, a ganglioside bearing the Pr2 antigenic determinant. In contrast to previous reports that indicated a possible temperature dependent self-association of IgM molecules via an immunological interaction leading to cold precipitation, we could not detect any affinity of this cryoglobulin for IgM when we used passive hemagglutination or an indirect enzyme-linked immunosorbent assay (ELISA). However, a GM3-like ganglioside could be extracted, by drastic methods, from the cryoglobulin studied at 22 degrees C, whereas no GM3 was extracted from two control cryoglobulins. Some minor gangliosides (representing less than 25% of total amount of bound gangliosides) were also extracted from Mou cryoglobulin and these gangliosides were shown to crossreact with GM3, as they specifically bind to Mou cryoglobulin by ELISA. After cryoprecipitation the serum still contained a monoclonal anti-Pr2 IgM kappa. A GM3-like ganglioside could be extracted from this purified IgM, and cryoprecipitability could be induced by the addition of a minute amount of micellar GM3. These results suggest that Mou cryoglobulin circulates as an immune complex and that cryoprecipitation may depend on unique IgM-GM3 (or IgM-GM3 cross-reacting gangliosides) complexes.

Ganglioside distribution at different levels of organization and its biological implications

The molecular diversity and complexity of gangliosides are surveyed in nervous and various extraneural tissues with particular emphasis on the different levels of organization such as tissues, cell types, subcellular structures, some cell organelles and topographical molecular membrane architecture. The characteristics revealed with such survey are discussed in an attempt to elucidate their cell biological background.