title: Rosette formation by macrophages with adhered T lymphocytes is precluded by inhibitors of antigen processing and presentation.
abstract: We had previously found in autologous human leukocyte cultures, in which dead neutrophils phagocytosis by macrophages occur, macrophages and T CD4 lymphocytes perform a selective cell-cell interaction showing many figures of either one, two or several T- lymphocytes adhering to a central macrophage were seen. Considering that antigen presentation would be necessary for the formation of these immune synapses, we attempted to block rosette formation (i.e., the formation of macrophage associations with at least three lymphocytes) by interfering with both antigen processing and presentation. Culture samples of autologous leukocytes from 7 healthy donors were subjected to either brefeldin A, chloroquine or to an anti-HLA DR antibody. Rosette formation was significantly inhibited in the treated samples (either with brefeldin A, chloroquine or the anti- HLA DR; ANOVA, p<0.001, as compared with the untreated controls). It is concluded that interference with antigen processing and presentation precludes the formation of these cell-cell interactions.
authors.affiliation: Instituto de Biología Celular, Facultad de Ciencias Médicas, Universidad Nacional de Córdoba, Av. Enrique Barros, Ciudad Universitaria, 5000 Córdoba, Argentina.
authors.forename: Ivón Teresa
authors.initials: IT
authors.lastname: Novak
authors.forename: Humberto Ramón
authors.initials: HR
authors.lastname: Cabral
mesh_terms: D000293:Adolescent; D000328:Adult; D017951:Antigen Presentation / Q000276:immunology*; D018501:Antirheumatic Agents / Q000494:pharmacology; D020126:Brefeldin A / Q000494:pharmacology; D002448:Cell Adhesion / Q000502:physiology*; D002478:Cells, Cultured; D002738:Chloroquine / Q000494:pharmacology; D005260:Female; D006684:HLA-DR Antigens / Q000276:immunology; D006801:Humans; D008264:Macrophages / Q000166:cytology / Q000187:drug effects / Q000276:immunology*; D008297:Male; D008875:Middle Aged; D011500:Protein Synthesis Inhibitors / Q000494:pharmacology; D013601:T-Lymphocytes / Q000166:cytology / Q000187:drug effects / Q000276:immunology*
chemical_list: D018501:Antirheumatic Agents; D006684:HLA-DR Antigens; D011500:Protein Synthesis Inhibitors; D020126:Brefeldin A; D002738:Chloroquine