Helper T cells discriminate among different antigen-presenting cells to provide their help in a selective fashion. The molecular mechanisms leading to this exquisite selectivity are still elusive. Here, we demonstrate that immunological synapses are dynamic and adaptable structures allowing T cells to communicate with multiple cells. We show that T cells can form simultaneous immunological synapses with cells presenting different levels of antigenic ligands but eventually polarize toward the strongest stimulus. Remarkably, living T cells form discrete foci of signal transduction of different intensities during the interaction with different antigen-presenting cells and rapidly relocate TCR and Golgi apparatus toward the cell providing the strongest stimulus. Our results illustrate that, although T cell activation requires sustained signaling, T cells are capable of rapid synapse remodeling and swift polarization responses. The combination of sustained signaling with preferential and rapid polarization provides a mechanism for the high sensitivity and selectivity of T cell responses.
Depoil, D., Zaru, R., Guiraud, M., Chauveau, A., Harriague, J., Bismuth, G., … Valitutti, S. (2005). Immunological synapses are versatile structures enabling selective T cell polarization. Immunity, 22(2), 185–194. https://doi.org/10.1016/j.immuni.2004.12.010