title: Use of TIRF to Monitor T-Lymphocyte Membrane Dynamics with Submicrometer and Subsecond Resolution.
abstract: A key step of adaptive immune responses is the T lymphocyte capacity to detect the presence of foreign antigens on specialized cells with high speed and specificity during contacts lasting a few minutes. Much evidence suggests that there is a deep link between the lifetime of molecular interactions between T cell receptors and ligands and T cell activation, but the precise mechanisms of bond formation and dissociation remain incompletely understood. Previous experiments done with interference reflection microscopy/reflection interference contrast microscopy disclosed transverse motions with several nanometer average amplitude of micrometer size membrane zones. More recently, total internal reflection fluorescence microscopy was used to show that the initial interaction between primary T lymphocytes and model surfaces involved the tip of microvilli (typically 0.2µm2area) generating apparent contacts of a few seconds that allowed cells to detect ligands of their membrane receptors. Here we show that these microvilli displayed minimal lateral displacements but quantitative fluorescence measurement suggested the occurrence of spontaneous transverse fluctuations of order of 67 nm amplitude during 1-s observation periods. This may play a major role in membrane receptor engagement and ensuing signal generation.
authors: Laboratoire Adhésion et Inflammation, Parc Scientifique de Luminy, Aix-Marseille Université, INSERM U1067, Case 937, 13288 Marseille Cedex 09, France ; INSERM U 1067, 13288 Marseille Cedex 09, France ; CNRS U 7333, 13288 Marseille Cedex 09, France.
authors: Alexandre
authors: A
authors: Brodovitch
authors: Laboratoire Adhésion et Inflammation, Parc Scientifique de Luminy, Aix-Marseille Université, INSERM U1067, Case 937, 13288 Marseille Cedex 09, France ; INSERM U 1067, 13288 Marseille Cedex 09, France ; CNRS U 7333, 13288 Marseille Cedex 09, France.
authors: Laurent
authors: L
authors: Limozin
authors: Laboratoire Adhésion et Inflammation, Parc Scientifique de Luminy, Aix-Marseille Université, INSERM U1067, Case 937, 13288 Marseille Cedex 09, France ; INSERM U 1067, 13288 Marseille Cedex 09, France ; CNRS U 7333, 13288 Marseille Cedex 09, France ; Assistance-Publique, Hôpitaux de Marseille, Marseille, France.
authors: Pierre
authors: P
authors: Bongrand
authors: Laboratoire Adhésion et Inflammation, Parc Scientifique de Luminy, Aix-Marseille Université, INSERM U1067, Case 937, 13288 Marseille Cedex 09, France ; INSERM U 1067, 13288 Marseille Cedex 09, France ; CNRS U 7333, 13288 Marseille Cedex 09, France.
authors: Anne
authors: A
authors: Pierres
keywords: Antigen detection; Interface; Membrane movement; Microvilli; T-lymphocyte; Total internal reflection fluorescence