Collab. C. Boyer (CIML), A Van der Merwe (Oxford)
The detection of foreign material by T lymphocytes is both a key step of immune responses and a model of cell decision triggering. We addressed this model by several parallel approaches based on quantitative advanced biophysical methods. We measured the properties of single TCR binding on the cell surfaces with atomic force microscopy (AFM, PLoS ONE 2011) and laminar flow chamber (Biophys. J. 2012). T cell activation appears as dependent of TCR bonding lifetime under low force.
Traces of surface exploration by a T-lymphocyte on different substrates imaged with TIRF.
We measured the dynamics of T cell membrane interactions with planar surface with nearly nanometric and subsecond resolution, using reflection interference contrast microscopy (RICM) and evanescent wave illumination (TIRF). We found that T cells could detect the presence of foreign material within less than 10 seconds with highly motile microvilli and pulling motion (J. Immunol. 2013), starting ultimately active spreading, the earliest reporter of bona fide cell activation (J. Immunol. Methods 2011). T cells could quantitatively discriminate between specific antigens of varying potency within 45 seconds after initial contact (Eur. J. Immunol 2015). Quantitative analysis of TIRF images revealed that T cell plasma membranes displayed transverse undulations of several tens of nanometer amplitude at one hertz frequency (Cell Mol Bioengineering, 2015), an efficient way of mechanosensing the nearby surface through the TCR. The importance and significance of addressed problems was discussed in two review papers (Frontiers Immunol 2012; Annual Rev. Immunol 2015).
Brodovitch A, P Bongrand, A Pierres (2013) J. Immunol. 191:2064-2071. Pubmed.
Brodovitch A, Limozin L, Bongrand P, Pierres A (2015) Cell. Mol. Bioeng. 8: 178-186. Pubmed
Puech P-H, D. Nevoltris, P. Robert, L. Limozin, C. Boyer, P. Bongrand (2011) PLoS ONE 6: e22344. Pubmed
Robert P, M Aleksic, O Dushek, V Cerundolo, P. Bongrand, PA van der Merwe (2012) . Biophys. J. 102:248-257. Pubmed