Fig. 1.
The supported lipid bilayer allows visualization of the T cell cortical actin cytoskeleton during immunological synapse formation. (A) Schematic outline of the experiment. T cells interact with a supported lipid bilayer functionalized with APC proteins. Centripetal flow of the actin cytoskeleton causes TCR microclusters to coalesce and translocate until they reach a chromium barrier (Cr), where they accumulate. The ICAM-1 APC protein (not shown) is also included and interacts with T cell LFA-1. Ni2+-DOGS lipids (purple circles) and the TIRF illumination beam (cyan) are not labeled. (B–G) TIRF microscopy images of TCRs, the actin cytoskeleton and ICAM-1, as well as bright field and reflection interference contrast microscopy (RICM) images of a cell on a grid-patterned substrate show a typical frustrated immunological synapse. Scale bar: 5 μm.