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L Graf

Publications and source records attributed to L Graf.

At least 73 records · Page 4Linked to original sources
PubMed1976

Isolation of a novel lipid hapten, cytolipin S, from rat spleen.

Antisera against rat erythrocytes contain agglutinins directed against unknown lipid determinants. Complement-fixation shows more reactivity with lipid extracts of rat spleen than of other rat tissues. The isolation of the reactive lipid from rat spleen, cytolipin S, is described. Cytolipin S is a glycosphingolipid containing glucose, galactose, and galactosamine with molar ratios of 1:2:1. It migrates on TLC like asialo GM1 (more slowly than cytolipin R, a ceramide tetrasaccharide, or cytolipin F, a ceramide pentasaccharide). Asialo GM1 and cytolipin S, when properly combined with auxiliary lipids, react very similarly with anti-rat erythrocyte sera by complement-fixation. However, cytolipin S is much more effective than asialo GM1 in inhibiting the hemagglutination reactions. It is concluded that cytolipin S and asialo GM1 are ceramide tetrasaccharides having different chemical structures and that the structural differences probably will be found in the carbohydrate linkages other than that between the terminal and penultimate residues.

Animals↗
PubMed1975

Immunochemical studies of organ and tumor lipids XXI. Sensitivity and specificity of the cytolipin F - sheep erythrocyte system.

The sensitivity and specificity of the sheep erythrocyte - anti-sheep erythrocyte system to inhibition by pure cytolipin F has been studied with 5 antisera, in order to compare it with the rat erythrocyte-anti-rat lymphosarcoma system and its inhibition by pure cytolipin R. The cytolipin F - sheep erythrocyte system is much more sensitive than the cytolipin R - rat erythrocyte system, inhibition of hemolysis of 6 x 10(6) sheep cells being produced by 10 ng of cytolipin F (combined with a four-fold quantity of lecithin) compared with inhibition of hemolysis of 10(6) rat cells by 50 to 100 ng of cytolipin R (also combined with lecithin). Differences in sensitivity are attributed to the larger number of available cytolipin F determinants on sheep erythrocytes compared with cytolipin R determinants on rat erythrocytes. Studies of the auxiliary lipid enhancement of cytolipin F activity by galactocerebroside, lactosyl ceramide (cytolipin H), and lecithin are also reported.

Animals↗
PubMed1972

Immunochemical studies of organ and tumor lipids. XIX. Cytolytic action of antibodies directed against cytolipin R.

Rabbit antisera to rat lymphosarcoma contain antibodies that are cytolytic for rat erythrocytes in the presence of complement. The reaction can be inhibited completely by pure cytolipin R showing that (a) immune hemolysis can be mediated through lipid determinants in the membrane, and (b) that cytolipin R determinants are present in the intact erythrocyte membrane and exposed on the surface. Optimal conditions for measurement of cytolysis in this system based on release of (51)Cr are described. Degrees of specificity of a number of different antilymphosarcoma sera are shown, based on inhibition of cytolysis by cytolipin R, cytolipin K, cytolipin H, cytolipin F (F-hapten), glucocerebroside, galactocerebroside, ceramide trisaccharide (cer-glu-gal-gal), and a mixed brain ganglioside preparation. The data suggest that cytolytic antibodies and agglutinating antibodies in these antisera are distinctive despite their common specificity for cytolipin R. Lymphosarcoma cells are more effective than erythrocytes in absorbing cytolytic antibodies.

Animals↗
PubMedDate not supplied

Effect of two synthetic alpha-gliadin peptides on lymphocytes in celiac disease: identification of a novel class of opioid receptors.

Two synthetic peptides containing residues 43-47 and 43-49 of alpha-gliadin were tested for inhibition of leukocyte migration in 47 patients with celiac disease. In nineteen patients, all on a normal diet, leukocyte migration was inhibited by the peptides and naloxone blocked this effect. In twenty-eight patients (24 of whom were on strict gluten-free diet) leukocyte migration was not affected by the peptides. Our results suggest that alpha-gliadin-(43-49), Tyr-Pro-Gln-Pro-Gln-Pro-Phe, is closely related to the active fragment, or to one of the active fragments of alpha-gliadin, and that it interacts with receptors that are similar to but not identical with the known opiate receptors.

Adolescent↗