Effects of chronic injection of sphingomyelin-containing liposomes on lymphoid and non-lymphoid cells in the spleen. Transient suppression of marginal zone macrophages
article
Mice were injected with sphingomyelin/cholesterol or phosphatidylcholine/cholesterol (PC/C) liposomes, from twice up to 10 times, on alternate days. Administration of sphingomyelin/cholesterol (SM/C) liposomes gave rise to hepato and spleno-megaly, microgranulomatous infections and changes in macrophage numbers and activity in spleen and liver. Enzyme and immuno-cytochemical methods were used, to demonstrate the effect of liposomes on the lymphoid and non-lymphoid cell populations, on cryostat sections of the spleen. Routine histological staining, of sphingomyelin/cholesterol treated animals, showed no drastic changes in morphology or compartmentalization of the spleen, apart from a small enlargement (with some microgranulomas) of the red pulp. No significant differences were found in the presence or localization of T-helper, T-cytotoxic/suppressor, T-total-lymphocytes, B-total-lymphocytes, red pulp macrophages, marginal metallophils, or non-lymphoid dendritic cells. However, a transient suppression of cells expressing marginal zone macrophage surface marker ERTR-9, was observed between the second and eighth (intravenous) administration of sphingomyelin/cholesterol liposomes. Immunization of these animals with trinitrophenyl (TNP)-ficoll, a thymus-independent type-2 antigen which is specifically processed by marginal zone macrophages (MZM), showed that these cells were not suppressed with regard to their immunological function. We conclude that chronic administration of sphingomyelin liposomes influences macrophages, probably through a general phagocytic-system overload, but no permanent or damaging changes in splenic cell populations or immunological functions occur.
Chemicals/CAS: cholesterol, 57-88-5; phosphatidylcholine, 55128-59-1, 8002-43-5; sphingomyelin, 85187-10-6; Ficoll, 25702-74-3; Immunoglobulins; Liposomes; Sphingomyelins; TNP-ficoll; Trinitrobenzenes
Chemicals/CAS: cholesterol, 57-88-5; phosphatidylcholine, 55128-59-1, 8002-43-5; sphingomyelin, 85187-10-6; Ficoll, 25702-74-3; Immunoglobulins; Liposomes; Sphingomyelins; TNP-ficoll; Trinitrobenzenes
Topics
CholesterolDrug carrierPhosphatidylcholineSphingomyelinAnimal cellAnimal experimentHistochemistryHistologyIntraperitoneal drug administrationIntravenous drug administrationLymphocyte subpopulationMacrophageMouseNonhumanPriority journalSpleenT lymphocyteAnimalFemaleFicollImmunoglobulinsLiposomesMacrophagesMiceMice, Inbred BALB CMice, Inbred C3HSphingomyelinsSpleenTrinitrobenzenes
TNO Identifier
230769
ISSN
00071021
Source
British Journal of Experimental Pathology, 69(6), pp. 865-875.
Pages
865-875
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