Isolation and characterization of the major acidic glycosphingolipids from the liver of the English sole (Parophrys vetulus). Presence of a novel ganglioside with a Forssman antigen determinant.
(33/69)
Acidic glycosphingolipids of the liver of English sole, Parophrys vetulus, have been isolated and characterized by 1H nuclear magnetic resonance spectroscopy, methylation analysis, and by direct probe electron-impact and fast atom bombardment mass spectrometry. In addition to the acidic glycosphingolipids with known structures (sulfatide, GM4, GM3, GM2, and GD1a), two fractions of a major monosialosylganglioside with TLC mobility slower than GM1 were isolated and characterized as having the following structure. (Formula:q see text). The structure represents a novel combination of a terminal Forssman disaccharide (GalNAc alpha 1----3GalNAc beta 1----3R) and a GM1 ganglioside core linked together. The identity of the terminal Forssman disaccharide was further established by TLC immunostaining with an anti-Forssman monoclonal antibody. This antibody showed strongly positive staining of the ganglioside only after removal of the sialic acid. Thus, the II3NeuAc residue inhibited antibody binding to the terminal disaccharide unit. Analysis of the ceramide moieties of both fractions indicated a predominance of 16:0, 22:1, 22:0, and 24:1 fatty acids in the faster migrating form and 16:0, 18:0, and 18:1 in the slower form in combination with d18:1 sphingosine. (+info)
Studies on the heterophile antibodies of infectious mononucleosis. I. Separation of four antibody populations, one of which contains lymphocytotoxic activity.
(34/69)
With the aid of insolubilized immunoadsorbents made with glycoproteins, extracted from cow red blood cells (RBC), and with guinea-pig kidney tissue, heterophile antibody populations of the Paul--Bunnell type and the Forssman type were eluted from infectious mononucleosis sera. Two Paul--Bunnell-type antibody populations were separated on the basis of their affinity for cow RBC antigens. The lymphocytotoxic antibodies in the infectious mononucleosis sera were eluted among the low-affinity Paul--Bunnell antibodies. (+info)
Cross-reactions between pneumococci and other streptococci due to C polysaccharide and F antigen.
(35/69)
By serological methods, all 83 known types of Streptococcus pneumoniae could be shown to possess C polysaccharide and F antigen. Cross-reactions due to these two antigens between pneumococci and a broad range of most other commonly encountered streptococci were examined. The presence of an antigen closely similar or identical to pneumococcal C polysaccharide was demonstrated in some strains of Streptococcus mitior. Therefore, we conclude that pneumococci cannot be identified serologically from mixed samples without culture. Streptococcal group C antiserum was found to cross-react with pneumococcal F antigen. (+info)
Analysis of NMR spectra of sugar chains of glycolipids by 1D homonuclear Hartmann-Hahn and NOE experiments.
(36/69)
We applied 1D homonuclear Hartmann-Hahn (1D-HOHAHA) and difference NOE experiments to determine the chemical structure of Forssman's antigen, a glycolipid purified from sheep red blood cells. The subspectra corresponding to the individual sugar components were extracted from overlapping proton resonances by selective excitation of the anomeric proton resonances, so that unambiguous assignments of the sugar proton resonances were accomplished. Then, difference NOE experiments were performed to determine the linkage of the sugar units. The present procedure was found to be useful for the structure determination of glycoconjugates and also reduces the amount of samples and machine time. (+info)
An ultrastructural analysis of the vascular damage in the lethal and sublethal Forssman reaction in the guinea-pig.
(37/69)
The involvement of the complement system and platelets in the sublethal Forssman reaction in the guinea pig has been studied together with the ultrastructural changes observed in the endothelial cells of the pulmonary vasculature. The main ultrastructural change noted was swelling of the endothelium. This did not occur in thrombocytopenic animals or in decomplemented animals, indicating the importance of both platelets and the complement pathways in this reaction. The platelet inhibitors sulphinpyrazone or aspirin had no effect on endothelial swelling in the sublethal reaction. In the lethal reaction the degree of endothelial cell damage was more severe and included lesions in the cell membrane, lifting, necrosis and finally exposure of the basement membrane. This damage only occurred in animals with an intact complement cascade. (+info)
Capping of exogenous Forssman glycolipid on cells.
(38/69)
When motile cells are incubated with Forssman glycolipid, the antigen is incorporated into the cells' plasma membranes. If cross-linked by antibody, the patched glycolipids cap. This process is sensitive to those drugs that are known to inhibit capping of protein antigens. The results support a flow mechanism for capping. (+info)
A new complement-mediated cytolytic mechanism--the C1-bypass activation pathway.
(39/69)
A new cytolytic pathway is described whereby cells sensitized with cytotoxic antibody can be specifically lysed in the complete absence of intact, classical complement pathway function. Evaluation of this model with sera deficient in the 4th (C4), 2nd (C2), and 6th (C6) components of complement has revealed that this new lytic mechanism, termed the C1-bypass activation pathway, is initiated by the antibody-mediated activation of C1. Utilizing components of the previously described alternate complement pathway, this pathway bypasses C4 and C2 to activate the third to ninth components of complement (C3-9) with induction of membrane damage. (+info)
Forssman glycolipid variants of dog gastric mucosa. Structure of a branched ceramide octasaccharide.
(40/69)
A fucose-containing ceramide octasaccharide exhibiting Forssman antigenic activity, and reacting in human H anti-H and anti-A systems, was isolated from water-soluble glycolipids of dog gastric mucosa. Defucosylation of the glycolipid resulted in the loss of H-activity, but had no effect on its Forssman nor blood-group A antigenic activity. The branched structure of glycolipid was identified by partial acid hydrolysis, sequential degradation with specific glycosidases and comparison of the permethylation products of the native and enzyme-degraded compound. The structure of this glycolipid is proposed to be: formula. (+info)