Crohn's disease alters MHC-rafts in CD4+T-cells

Clusters of MHCI, ICAM-1, CD44, CD59, IL-2R, and IL-15R molecules have been studied on the surface of CD4+ T-cells from peripheral blood and lymph nodes of patients in Crohn's disease and healthy individuals as controls by using a dual-laser flow cytometric fluorescence resonance energy transfer (FRET) technique and fluorescently stained Fabs. When cells from patients in Crohn's disease are compared to those of controls, the surface expression level for the MHCI reduced by similar to 45%, for CD44 enhanced by similar to 100%, and for IL-2Ra, IL-15Ra, and common ?c enhanced by similar to 50%, similar to 70%, and similar to 130%, respectively. Efficiencies of FRET monitoring homoassociation for the MHCI and CD44 reduced, that for IL-2Ra enhanced. While efficiencies of FRET monitoring the association of ?c and ICAM-1 with the MHCI reduced, those monitoring association of IL-2/15Ra, CD44, and CD59 with MHCI enhanced. Efficiencies of FRET measured between the MHCI and IL-2Ra, IL-15Ra differently enhanced to the advantage of IL-15Ra, the one measured between ?c and IL-2Ra reduced, suggesting modulations in the strength of interaction of MHCI with IL-2R, IL-15R, and ?c. The increases in density of surface bound cTx and in the associations of the receptors with the GM1-ganglioside lipid molecules suggest stronger lipid raft interactions of the receptors. The observed alterations of MHC-rafts in Crohn's diseasesummarized in models of receptor patterns of diseased and control cellsmay have functional consequences regarding signaling by the raft components. (C) 2011 International Society for Advancement of Cytometry