Photocrosslinkable pMHC monomers stain T cells specifically and cause ligand-bound TCRs to be 'preferentially' transported to the cSMAC.
The binding of T cell antigen receptors (TCRs) to specific complexes of peptide and major histocompatibility complex (pMHC) is typically of very low affinity, which necessitates the use of multimeric pMHC complexes to label T lymphocytes stably. We report here the development of pMHC complexes able to be crosslinked by ultraviolet irradiation; even as monomers, these efficiently and specifically stained cognate T cells. We also used this reagent to probe T cell activation and found that a covalently bound pMHC was more stimulatory than an agonist pMHC on lipid bilayers. This finding suggested that serial engagement of TCRs is dispensable for activation when a substantial fraction of TCRs are stably engaged. Finally, pMHC-bound TCRs were 'preferentially' transported into the central supramolecular activation cluster after activation, which suggested that ligand engagement enabled linkage of the TCR and its associated CD3 signaling molecules to the cytoskeleton.
Department of Microbiology and Immunology, Stanford University School of Medicine, Stanford, California, USA.
Jianming
J
Xie
Johannes B
JB
Huppa
Evan W
EW
Newell
Jun
J
Huang
Peter J R
PJ
Ebert
Qi-Jing
QJ
Li
Mark M
MM
Davis
D000818:Animals; D017252:CD3 Complex / Q000737:chemistry / Q000276:immunology; D002478:Cells, Cultured; D004396:Coloring Agents / Q000737:chemistry; D003432:Cross-Linking Reagents / Q000737:chemistry*; D003599:Cytoskeleton / Q000737:chemistry / Q000276:immunology; D008213:Lymphocyte Activation; D008285:Major Histocompatibility Complex / Q000276:immunology*; D051379:Mice; D008822:Mice, Transgenic; D011948:Receptors, Antigen, T-Cell / Q000737:chemistry* / Q000276:immunology; D015398:Signal Transduction / Q000276:immunology; D013601:T-Lymphocytes / Q000737:chemistry* / Q000276:immunology
D017252:CD3 Complex; D004396:Coloring Agents; D003432:Cross-Linking Reagents; D011948:Receptors, Antigen, T-Cell