Immune synapse formation determines interaction forces between T cells and antigen-presenting cells measured by atomic force microscopy

doi:10.1073/pnas.0905384106

Immune synapse formation determines interaction forces between T cells and antigen-presenting cells measured by atomic force microscopy

^aDepartment of New Materials and Biosystems, Max-Planck-Institute for Metals Research, Stuttgart, Germany, and Department of Biophysical Chemistry, University of Heidelberg, Heisenbergstrasse 3, D-70569 Stuttgart, Germany;
^bDepartment of Molecular Immunology, German Cancer Research Center, D-69120 Heidelberg, Germany;
^cInstitute for Immunology, University of Heidelberg, Im Neuenheimer Feld 305, D-69120 Heidelberg, Germany; and
^dInstitute of Molecular and Clinical Immunology, Otto-von-Guericke-University-Magdeburg, Leipziger-Strasse 44, D-39120 Magdeburg, Germany

Edited by Michael Sela, Weizmann Institute of Science, Rehovot, Israel, and approved September 3, 2009 (received for review May 19, 2009)

Abstract

During adaptive immune responses, T lymphocytes recognize antigenic peptides presented by MHC molecules on antigen-presenting cells (APCs). This recognition results in the formation of a so-called immune synapse (IS) at the T-cell/APC interface, which is crucial for T-cell activation. The molecular composition of the IS has been extensively studied, but little is known about the biophysics and interaction forces between T cells and APCs. Here, we report the measurement of interaction forces between T cells and APCs employing atomic force microscopy (AFM). For these investigations, specific T cells were selected that recognize an antigenic peptide presented by MHC-class II molecules on APCs. Dynamic analysis of T-cell/APC interaction by AFM revealed that in the presence of antigen interaction forces increased from 1 to 2 nN at early time-points to a maximum of ≈14 nN after 30 min and decreased again after 60 min. These data correlate with the kinetics of synapse formation that also reached a maximum after 30 min, as determined by high-throughput multispectral imaging flow cytometry. Because the integrin lymphocyte function antigen-1 (LFA-1) and its counterpart intercellular adhesion molecule-1 (ICAM-1) are prominent members of a mature IS, the effect of a small molecular inhibitor for LFA-1, BIRT377, was investigated. BIRT377 almost completely abolish the interaction forces, emphasizing the importance of LFA-1/ICAM-1-interactions for firm T-cell/APC adhesion. In conclusion, using biophysical measurements, this study provides precise values for the interaction forces between T cells and APCs and demonstrates that these forces develop over time and are highest when synapse formation is maximal.

Footnotes

¹To whom correspondence should be addressed. E-mail: hammerling{at}dkfz.de
Author contributions: B.H.H., I.L., D.D., Y.S., M.G., J.P.S., and G.J.H. designed research; B.H.H., D.D., G.H.W., J.D., and N.B. performed research; B.H.H., I.L., G.H.W., and G.J.H. analyzed data; and B.H.H. and G.J.H. wrote the paper.
The authors declare no conflict of interest.
This article is a PNAS Direct Submission.
This article contains supporting information online at www.pnas.org/cgi/content/full/0905384106/DCSupplemental.