| First Author | Graf B | Year | 2007 |
| Journal | J Immunol | Volume | 179 |
| Issue | 3 | Pages | 1616-24 |
| PubMed ID | 17641028 | Mgi Jnum | J:149948 |
| Mgi Id | MGI:3849400 | Doi | 10.4049/jimmunol.179.3.1616 |
| Citation | Graf B, et al. (2007) LFA-1-mediated T cell costimulation through increased localization of TCR/class II complexes to the central supramolecular activation cluster and exclusion of CD45 from the immunological synapse. J Immunol 179(3):1616-24 |
| abstractText | T cell activation is associated with a dramatic reorganization of cell surface proteins and associated signaling components into discrete subdomains within the immunological synapse in T cell:APC conjugates. However, the signals that direct the localization of these proteins and the functional significance of this organization have not been established. In this study, we have used wild-type and LFA-1-deficient, DO11.10 TCR transgenic T cells to examine the role of LFA-1 in the formation of the immunological synapse. We found that coengagement of LFA-1 is not required for the formation of the central supramolecular activation cluster (cSMAC) region, but does increase the accumulation of TCR/class II complexes within the cSMAC. In addition, LFA-1 is required for the recruitment and localization of talin into the peripheral supramolecular activation cluster region and exclusion of CD45 from the synapse. The ability of LFA-1 to increase the amount of TCR engaged during synapse formation and segregate the phosphatase, CD45, from the synapse suggests that LFA-1 might enhance proximal TCR signaling. To test this, we combined flow cytometry-based cell adhesion and calcium-signaling assays and found that coengagement of LFA-1 significantly increased the magnitude of the intracellular calcium response following Ag presentation. These data support the idea that in addition to its important role on regulating T cell:APC adhesion, coengagement of LFA-1 can enhance T cell signaling, and suggest that this may be accomplished in part through the organization of proteins within the immunological synapse. |
