SUPRAMOLECULAR RECEPTOR STRUCTURES IN THE PLASMA-MEMBRANE OF LYMPHOCYTES REVEALED BY FLOW CYTOMETRIC ENERGY-TRANSFER SCANNING FORCE-MICRSCOPIC AND TRANSMISSION ELECTRON-MICROSCOPIC ANALYSES

Receptors ill the plasma membrane of blood cells in general and in tha t of lymphocytes in particular are supposed to move around in a random walk fashion relatively freely driven by thermal diffusion, as descri bed by the Singer-Nicolson fluid mosaic membrane model. In this articl e we summarized data and techniques that indicated nonrandom codistrib ution patterns of receptor superstructures under conditions, where the generation of such molecular colocalizations by the methods themselve s were excluded. Application of fluorescence energy transfer in a flow cytometer helped to analyze such codistribution patterns in cell popu lations. After normalizing energy transfer values for possible differe nces between labeling ratios of the targeting monoclonal antibodies an d using the mean values of energy transfer distribution curves, two-di mensional receptor maps mere generated from data obtained in a pair-wi se fashion between receptors, Major histocompatibility complex (MHC) c lass I and II, intercellular adhesion molecule-1 (ICAM-1), TcR-CD3-CD4 , tetraspan molecules (CD81, CD82, CD53), and the subunits of the mult isubunit IL-2 receptor displayed nonrandom codistribution patterns som etimes with, but very frequently without induction by their ligand, Im munogold-bead ''sandwich'' labeling analyzed by atomic force microscop y has shown that such receptor ''islands'' existed also in ''receptor- island-groups''. This indicated the existence of nonrandom receptor di stribution of MHC class I and II molecules also at an elevated hierarc hical level. An analysis is given herein concerning a standardized app roach. The apparent incompatibility of these supramolecular patterns w ith the Singer-Nicolson type ''free-protein and lipid-mobility paradig m'' was resolved by recommending an additional emphasis on the mosaici sm of the membrane besides receptor mobility (C) 1998 Wiley-Liss,Inc.