RESUMO
Gangliosides of macrophages are potent immunoregulatory molecules. A monoclonal antibody directed at human macrophage gangliosides (25F4) inhibits macrophage migration with relative specificity. Recent reports suggested that greater expression of G(M1) in mononuclear cells accompanies advanced HIV infection, although others failed to demonstrate any differences in vitro. We purified gangliosides from blood monocyte-derived macrophages obtained from HIV-infected adults. Densitometric analysis of chromatograms demonstrated no differences in relative quantities of any macrophage gangliosides among all HIV-positive and -negative donors. Antibody 25F4 showed equivalent ELISA reactivity with purified macrophage gangliosides of HIV-positive and -negative donors. However, intact macrophages of HIV donors with CD4+ cell counts <200/mm3 showed impaired immunofluorescent surface expression of the 25F4 epitope and concomitant loss of migration inhibitory responsiveness. Thus, although relative content is unchanged, macrophage gangliosides become surface-inaccessible in adults with advanced HIV infection. Our data provide further evidence that dysregulation of glycosphingolipid metabolism in HIV-1 infection contributes to immune dysfunction.
Assuntos
Gangliosídeos/sangue , Infecções por HIV/sangue , Macrófagos/metabolismo , Monócitos/metabolismo , Adulto , Anticorpos Monoclonais/farmacologia , Sequência de Carboidratos , Membrana Celular/fisiologia , Inibição de Migração Celular , Progressão da Doença , Ensaio de Imunoadsorção Enzimática , Imunofluorescência , Fluorometria , Soronegatividade para HIV , Soropositividade para HIV/sangue , Humanos , Macrófagos/citologia , Macrófagos/efeitos dos fármacos , Masculino , Pessoa de Meia-Idade , Dados de Sequência Molecular , Monócitos/citologia , Monócitos/efeitos dos fármacosRESUMO
An in vitro method for detecting toxin produced by Aphanizomenon flos-aquae is described. This procedure is more sensitive than the mouse toxicity test and is based on viability changes in human leukocytes.