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Modification of α2-macroglobulin into a macrophage-activating factor through the action of liposome-stimulated B-cell membranous glycosidases.
- Source :
- Immunology; Sep95, Vol. 86 Issue 1, p58-63, 6p
- Publication Year :
- 1995
-
Abstract
- The serum glycoprotein α<subscript>2</subscript>-macroglobulin can be converted into a potent macrophage-activating factor that promotes the Fcγ receptor-mediated phagocytosis of macrophages, through modification of the sugar moiety with liposome-treated B-cell glycosidase(s). This paper discusses the activation mechanism of B-cell membranous glycosidase by liposomes using mouse splenic B cells. B-cell membranous β-galactosidase and βN-acetylglucosaminidase were significantly activated by liposome treatment, and this process can be regulated by trypsin-sensitive protein. To clarify the contribution of trypsin-sensitive protein to enzyme activities, the B-cell surface antigen receptor was studied. With the addition of a Fab′ fragment of anti-mouse IgM but not IgD antibody, the activation of both glycosidases induced by liposomes was significantly inhibited and was essentially the same as that of saline-treated glycosidase activities. Consequently, interactions of liposomes with cell-surface IgM may cause B-cell membranous glycosidase activation. A significant decrease in membrane fluidity, particularly near the membrane surface rather than deep within the membrane, was observed in liposome-treated B cells using electron spin resonance. Liposomes would thus appear to interact with B cells via cell-surface IgM, with a consequent decrease in membrane fluidity, as well as the activation of B-cell membranous glycosidases, causing α2-macroglobulin to be converted into a macrophage activating factor. [ABSTRACT FROM AUTHOR]
Details
- Language :
- English
- ISSN :
- 00192805
- Volume :
- 86
- Issue :
- 1
- Database :
- Complementary Index
- Journal :
- Immunology
- Publication Type :
- Academic Journal
- Accession number :
- 14087341