Biomedical subjects

F Schriever

Publications and source records attributed to F Schriever.

22 records · Page 2Linked to original sources

PubMed1989

Identification of a sulfoglycolipid epitope shared by cells of neuroectodermal and hematopoietic origin.

Monoclonal antibody (mAb) SNH.1 detects an epitope which is restricted to cells of neuroectodermal and hematopoietic origin. The mAb was obtained by immunization of a mouse with liposomes containing a crude extract of human melanoma acidic glycolipids. The SNH.1 antigen isolated from melanoma was identified as a sulfated glycolipid, closely related or identical to sulfogalactosyl-ceramide. When tested with different lipids, mAb SNH.1 reacted as well with other sulfoglycolipids. The staining of mAb SNH.1 is restricted to the cytoplasm and often localized to the perinuclear region. Therefore, the SNH.1 mAb epitope may be detectable only during the biosynthesis of sulfoglycolipids.

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PubMed1989

Monoclonal antibody MACG1 distinguishes between different molecular species of the ganglioside GM3.

The present study investigates the chemical structure of a ganglioside, detected by monoclonal antibody (MAb) MacG1, which reacts with intracytoplasmic granules of tumor-infiltrating macrophages. The results obtained by enzymatic hydrolysis and fast-atom bombardment-mass spectrometry reveal that MAb MacG1 reacts with a subcomponent of the ganglioside GM3 found in melanoma and bovine brain. MAb MacG1 might be a powerful tool to distinguish among GM3 species and could help to define their possibly different biological functions.

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PubMed1988

MACG1, a mouse monoclonal antibody detecting a monosialoganglioside expressed in tumor-infiltrating macrophages.

MacG1 is a mouse monoclonal antibody (mAb) directed against a ganglioside, which is differentially expressed by macrophages infiltrating malignant melanomas and benign melanocytic lesions. mAb MacG1 was obtained by immunization with liposomes containing a mixture of gangliosides extracted from malignant melanoma. The antibody was selected for binding to melanoma gangliosides and for reactivity with frozen tissue sections of malignant melanoma. mAb MacG1 showed reactivity in 25 of 46 melanomas examined but in only 1 of 51 nevi tested. The mAb did not react with melanoma cells but did with cytoplasmic granules and deposits associated with large dispersed cells, which were also found in some nonmelanomatous tumors and in some lymphoid tissues. Using mAbs directed against differentiation antigens these cells were identified as macrophages. In nearly all reactive tissues MacG1-positive macrophages accounted for a minority of the total macrophages. The difference in reactivity between malignant melanomas and nevi could not be explained by the variable numbers of total macrophages in these lesions. It is suggested that mAb MacG1 may define a functionally distinct subpopulation of tumor-infiltrating macrophages. Staining of cells other than macrophages was observed in some normal and malignant neural tissues. MacG1 bound to a monosialoganglioside extracted from melanoma and reacted only with NeuAc alpha 2-3Gal beta 1-4Glc-Cer when tested with a panel of ganglioside standards.

Animals↗

PubMed1988

Enzymatic degradation in phagocytic monocytes generates the ganglioside epitope defined by antibody MacG1.

Monoclonal antibody (mAb) MacG1 was recently shown to detect a monosialoganglioside expressed in tumor infiltrating macrophages. The present study demonstrates with in vitro experiments that the MacG1 epitope is generated during cellular digestion in phagocytic monocytes. Following phagocytosis and degradation of MacG1 negative sheep red blood cells, the MacG1 epitope was expressed in intracytoplamsic granules of murine plastic-adherent peritoneal cells. Stimulation of adherent cells and phagocytosis alone did not lead to the expression of the MacG1 epitope. Chloroquine, which inhibits the activity of lysosomal enzymes, prevented the generation of the MacG1 epitope. Reactivity with mAb MacG1 appears to reflect a specific step during the enzymatic degradation of gangliosides and the antibody may provide a unique tool for analyzing this pathway.

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