The role of membrane gangliosides in murine alveolar macrophage-mediated suppression of the immune response.
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.
Mbawuike
I N
IN
Department of Microbiology, Georgetown University, School of Medicine, Washington, D.C. 20007.
Herscowitz
H B
HB
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
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