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.
Schriever
F
F
Institute of Immunology, Müchen, FRG.
Riethmüller
G
G
Johnson
J P
JP
D000818:Animals; D000911:Antibodies, Monoclonal / Q000276:immunology*; D000939:Epitopes / Q000032:analysis*; D005732:Gangliosides / Q000276:immunology* / Q000378:metabolism; D051379:Mice; D009000:Monocytes / Q000276:immunology*; D010587:Phagocytosis
D000911:Antibodies, Monoclonal; D000939:Epitopes; D005732:Gangliosides