Co-receptors CD4 and CD8 are essential for the development and function of T cells. However, molecular mechanism how CD4, and to some extend CD8, modulate T cell response to antigens remains elusive. This is in part due to a lack of information on the nanoscopic organisation of these molecules with respect to the TCR signalling machinery and topology of T cell membrane. Such detailed analysis can be only achieved by the state-of-the-art microscopy which allows visualisation of nanoscopic details. Here, we will employ our recently developed super-resolution methods to determine organisation of early TCR signalling machinery in microvilli of resting T cells with highest possible precision of ~20 nm in 3D. We will further test potential of CD4 to affect T cell sensitivity to diverse ligands by co-localisation with the receptor and selected effector molecules in microvilli. Altogether, our work should provide a novel insight into the initial phase of T cell antigen recognition by microvilli-associated molecules.