Nanoscale 3D profiling of the T cell membrane reveals CD2 enrichment at microvilli tips, positioning adhesion near TCR zones in the immunological synapse

The T cell membrane features a specialized molecular and topological organization critical for signaling and immune function. During antigen detection, T cells utilize finger-like protrusions called microvilli to dynamically scan the antigen-presenting cell (APC) surface. Enriched with T cell receptors (TCRs) and key signaling molecules, microvilli serve as primary signaling hubs, yet their nanoscale architecture remains poorly defined. Upon antigen engagement, TCR activation drives the formation of the immunological synapse (IS), a highly organized membrane contact with the APC critical for T cell function. However, profiling IS architecture at the nanoscale remains technically challenging. Here, we introduce NanoMAP (Nanoscale Membrane Architecture Profiling), an expansion microscopy-based platform that resolves receptor organization on T cell microvilli and within the IS at 35-60 nm resolution. Using NanoMAP, we show that effector CD8+ T cells possess a 5.1-fold higher microvillar density than naive CD8+ T cells. Mapping the adhesion receptors CD2 and LFA-1 on the T cell surface reveals that CD2 exhibits a stronger preference for localizing to microvilli tips compared to TCR and LFA-1. Within microvilli, CD2 displays a strong spatial association with TCR clusters, contrasting with a markedly weaker TCR-LFA-1 association. At the IS, TCR and CD2 co-occupy close membrane contacts, while LFA-1 is excluded to more distal regions. Upon termination of activation, TCR clusters selectively disengage from microvilli, whereas CD2 and LFA-1 persist. These results suggest a coordinated, activation-dependent organization of adhesion receptors that drives microvillar adhesion during scanning and stabilizes IS membrane contacts. Together, NanoMAP establishes a powerful framework for dissecting nanoscale membrane architecture and spatial signaling in T cells.