title: The role of membrane gangliosides in murine alveolar macrophage-mediated suppression of the immune response.
abstract: Generation of aldehydes on cell membranes of viable alveolar macrophages (AM) by mild oxidation with sodium periodate was previously shown to result in total abrogation of AM-mediated suppression of the plaque-forming cell (PFC) response of spleen cells previously primed with sheep erythrocytes (SRBC). These results suggested a possible role for macrophage sialoglycoconjugates, such as gangliosides and sialoglycoproteins, in suppression. In the present report, it is shown that a purified mixture of gangliosides suppressed the PFC response of SRBC-primed spleen cells in a dose-dependent manner. Addition of rabbit anti-mouse brain antiserum (RAMB), which reacts with the gangliosides, reversed both ganglioside- and AM-mediated suppression of the PFC response. Pretreatment of AM but not spleen cells with RAMB also resulted in the reversal of AM-mediated suppression. The expression of gangliosides on the membrane of AM was detected with RAMB in an enzyme-linked immunosorbent assay (ELISA). The results suggest that membrane gangliosides may play an important role in the AM-mediated suppression of the PFC response. Since paraformaldehyde-fixed AM were not suppressive, it is speculated that AM release the suppressive gangliosides into the culture medium and rabbit anti-mouse brain antibody either prevents their release and/or neutralizes the suppressive function of released gangliosides.
authors.affiliation: Department of Microbiology, Georgetown University, School of Medicine, Washington, D.C. 20007.
authors.forename: I N
authors.initials: IN
authors.lastname: Mbawuike
authors.forename: H B
authors.initials: HB
authors.lastname: Herscowitz
mesh_terms: D000818:Animals; D000911:Antibodies, Monoclonal / Q000502:physiology; D000917:Antibody Formation / Q000187:drug effects; D001921:Brain / Q000276:immunology; D004797:Enzyme-Linked Immunosorbent Assay; D005557:Formaldehyde / Q000494:pharmacology; D005732:Gangliosides / Q000502:physiology*; D006462:Hemolytic Plaque Technique; D007106:Immune Sera / Q000494:pharmacology; D007166:Immunosuppressive Agents / Q000502:physiology*; D007518:Isoantibodies / Q000502:physiology; D008264:Macrophages / Q000187:drug effects / Q000276:immunology*; D008563:Membrane Lipids / Q000502:physiology*; D051379:Mice; D008807:Mice, Inbred BALB C; D011108:Polymers / Q000494:pharmacology; D011650:Pulmonary Alveoli / Q000166:cytology; D011817:Rabbits; D013154:Spleen / Q000166:cytology
chemical_list: D000911:Antibodies, Monoclonal; D005732:Gangliosides; D007106:Immune Sera; D007166:Immunosuppressive Agents; D007518:Isoantibodies; D008563:Membrane Lipids; D011108:Polymers; C035678:anti-Thy antibody; D005557:Formaldehyde; C003043:paraform