Rosette formation by macrophages with adhered T lymphocytes is precluded by inhibitors of antigen processing and presentation

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.

Enfermedad de Chagas: persistente produccion de una glicoproteina de linfocitos T en pacientes tratados con agentes anti Trypanosoma cruzi. / Chagas' disease: persistent production of a glycoprotein of T-lymphocytes in patients treated with antiTrypanosoma cruzi agents

Alto numero de linfocitos T circulantes en pacientes con enfermedad de Chagas son ricos en una sustancia PAS-positiva citoplasmatica (PASPLS), que reacciona como glicoproteina. En el presente trabajo se demuestra que esa sustancia (PASPLS) esta presente tambien en linfocitos de pacientes chagasicos que fueron tratados con drogas anti Trypanosoma cruzi varios anos antes de este estudio. Se hallo que todos mostraron un alto numero de linfocitos circulantes poseedores de PASPLS, tal como los chagasicos no tratados. La correlacion con otros datos del seguimiento de los pacientes tratados sugiere que la intensa actividad PASPLS-productora descrita como caracteristica de Chagas seria mantenida a traves de memoria inmunologica una vez iniciado el fenomeno. Ademas, se registro un avance o, en ciertos casos, la aparicion de manifestaciones clinicas de Chagas, en varios de los tratados con los agentes anti Trypanosoma cruzi, aunque sus parasitemias se negativizaron en todos y en varios casos desaparecieron ademas los anticuerpos anti Trypanosoma cruzi fijadores del complemento. Se estima que sera de interes ampliar la discusion sobre esas evidencias cuando esten disponibles mas datos sobre el fenomeno de PASPLS-produccion en Chagas