Adhesion? Sticking & Signalling

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Adhesion? Sticking & Signalling. E. Yvonne Jones Erice 2006. T cell target cell interactions, a particular form of cell-cell communication with specificity contributed by pMHC TCR binding. Result: T cell receptor (TCR) signalling and formation of an Immunological Synapse. - PowerPoint PPT Presentation

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  • Adhesion?

    Sticking &SignallingE. Yvonne JonesErice 2006

  • T cell target cell interactions, a particular form of cell-cell communication withspecificity contributed by pMHC TCR binding.Result: T cell receptor (TCR) signalling and formation of an ImmunologicalSynapse.

  • Immunodominant HLA-A2 tumour epitope NY-ESO-1157-165: SLLMWITQC SLLMWITQV stimulates faster polarisation of lytic granules to the immunological synapse Chen & Stewart-Jones et al (2005) J. Exp. Med. 201 1243-1255But, all pMHCs are not equal

  • Structure of the immunodominant bV17-aV10s2 T cell receptor with HLA A2/influenza matrix epitope

    ..as used by >one billion humans!and all TCRs are not equalStewart-Jones et al (2003) Nature Immunol. 4 657-663

  • V17 Flu Matrix T Cells- The Most Abundant T cell Clonotype on the PlanetAn estimated 3 billion people have HLA-A2All have had InfluenzaFlu matrix responses dominate the immune reaction to infectionV17 clonotype constitutes > 80% of that response 0.5 kg of this receptor circulating in the worldStacking the receptors end-to-end would stretch more than halfway to Neptune (2.6 billion km)

    Guillaume Stewart-Jones, Jeffrey Ishizuka & John Bell, unpublished calculation

  • Why is a bV17-aV10s2 TCRso good at recognising HLA A2/influenza matrix epitope?

  • Kuby, 4th edition

  • The potential TCR repertoire is further increased by the addition of N region nucleotides. The recombination process is not precise. the exact points of splicing between V, D and J regions can vary over several nucleotides extra nucleotides, called N regions, can also be inserted at these joints.

    The number of TCRs that we make is ~2.5 x 107

    T cell receptors (TCRs)Gene segmentsCombinationsV50J502.5 x 103 alpha chainsV20J13D2520 beta chainsAny alpha with any beta chain1.3 x 106

  • Flu matrixpeptide presentedby HLA-A2 providesfew sidechainsfor TCR recognitionThe challenge

  • TCR positioned to insert CRD3b between peptideand alpha 2 helixThe answer

  • Why is a bV17-aV10s2 TCRso good at recognising HLA A2/influenza matrix epitope?

    Its because of a distinctive CDR3b motifand combination of residues unique to bV17-aV10s2 CDR1 and CDR2 loopsthat allow the CDR3b to be positioned optimally to sample a unique feature of the pMHC surface Stewart-Jones et al (2003) Nature Immunol. 4, 657-663

  • sTCR mutants made and testedJeffrey Ishizuka & Guillaume Stewart-Jones

  • V17 CDR2 Offers a Unique Sequence and Energetic Landscape

  • So we are still on target with our hypothesis for why a bV17-aV10s2 TCR is so good at recognising HLA A2/influenza matrix epitope.

    But why is this TCR-pMHC immunodominant over all other TCR-pMHC interactions involving influenza virus epitopes presented by theMHC class I molecule HLA A2?

  • T cell target cell interactions, a particular form of cell-cell communication withspecificity contributed by pMHC TCR binding.Result: T cell receptor (TCR) signalling and formation of an ImmunologicalSynapse.

  • Receptor protein tyrosine phosphatases: classification

  • RPTPm expression on axonal growth cones (A and B, Ledig et al., 1999) and at the endothelial cell junctions (C and D, Bianchi et al., 1999).RPTPm is a cell-adhesion molecule involved in neural development (axon growth) and angiogenesis.RPTPm

  • Crystal structure of the MAM-Ig unit Aricescu & Hon (2006) EMBO J. 25 701-712 for dimersneedMIg-FNIIIand for adhesionneedMIg-2xFNIIIsostructurefunction?NO

  • MIg structure plus biophysical and functional data generatedseveral possible models for RPTPm adhesive interactions Zipper model, consistent with the extended planarity of the plasma membrane observed at intercellular contact sites and with the multiple interactions observed between RPTPm ectodomainsI recommend you go and see Radu Aricescus poster in the Thursday afternoon session

    (also Christian Siebolds poster on cell guidance signalling)

  • Christian SieboldRadu AricescuWeixian Lu(Jeffrey Ishizuka) &Guillaume Stewart-Jones In collaboration with: John Bell, Vincenzo Cerundolo,Andrew McMichael & Anton van der Merwe

    1G4 CTLT2 conjugates formation is very efficient when targets are loaded with ESO 9V peptide. The panel shows a series of selected images taken from the live-cell videos in Videos 1 and 2 (available at http://www.jem.org/cgi/content/full/jem.20042323/DC1). CTLs loaded with lysotracker green were added to the adherent T2 target cells pulsed with 1 M ESO 9C (AE; and Video 1) or pulsed with 1 M ESO 9V (FL; and Video 2). The images selected from the Video 1 correspond to time 0 (A) indicating the first contact of a CTL with T2 pulsed with ESO 9C, 5 min (B), 12 min, and 20 s (C), 15 min and 20 s (D), 22 min and 40 s (E) and the ones taken from Video 2 are, respectively: time 0 (F), 1 min and 40 s (G), 5 min and 40 s (H), 6 min and 20 s (I), and 9 min and 40 s (L). The Normaski differential interference contrast image (blue) and 1 M of green confocal image have been super-imposed at each time point. White, red, black, and light blue arrows indicate the CTLs described in the results. Bars, 10 m. 1G4 CTLT2 conjugates formation is very efficient when targets are loaded with ESO 9V peptide. The panel shows a series of selected images taken from the live-cell videos in Videos 1 and 2 (available at http://www.jem.org/cgi/content/full/jem.20042323/DC1). CTLs loaded with lysotracker green were added to the adherent T2 target cells pulsed with 1 M ESO 9C (AE; and Video 1) or pulsed with 1 M ESO 9V (FL; and Video 2). The images selected from the Video 1 correspond to time 0 (A) indicating the first contact of a CTL with T2 pulsed with ESO 9C, 5 min (B), 12 min, and 20 s (C), 15 min and 20 s (D), 22 min and 40 s (E) and the ones taken from Video 2 are, respectively: time 0 (F), 1 min and 40 s (G), 5 min and 40 s (H), 6 min and 20 s (I), and 9 min and 40 s (L). The Normaski differential interference contrast image (blue) and 1 M of green confocal image have been super-imposed at each time point. White, red, black, and light blue arrows indicate the CTLs described in the results. Bars, 10 m. 1G4 CTLT2 conjugates formation is very efficient when targets are loaded with ESO 9V peptide. The panel shows a series of selected images taken from the live-cell videos in Videos 1 and 2 (available at http://www.jem.org/cgi/content/full/jem.20042323/DC1). CTLs loaded with lysotracker green were added to the adherent T2 target cells pulsed with 1 M ESO 9C (AE; and Video 1) or pulsed with 1 M ESO 9V (FL; and Video 2). The images selected from the Video 1 correspond to time 0 (A) indicating the first contact of a CTL with T2 pulsed with ESO 9C, 5 min (B), 12 min, and 20 s (C), 15 min and 20 s (D), 22 min and 40 s (E) and the ones taken from Video 2 are, respectively: time 0 (F), 1 min and 40 s (G), 5 min and 40 s (H), 6 min and 20 s (I), and 9 min and 40 s (L). The Normaski differential interference contrast image (blue) and 1 M of green confocal image have been super-imposed at each time point. White, red, black, and light blue arrows indicate the CTLs described in the results. Bars, 10 m.