Visualizing the Functional Diversification of CD8+ T Cell Responses in Lymph Nodes

Abstract

CD8(+) T cell responses generate effector cells endowed with distinct functional potentials but the contribution of early events in this process is unclear. Here, we have imaged T cells expressing a fluorescent reporter for the activation of the interferon-γ (IFN-γ) locus during priming in lymph nodes. We have demonstrated marked differences in the efficiency of gene activation during stable T cell-dentritic cell (DC) contacts, influenced in part by signal strength. Imaging the first cell division, we have demonstrated that heterogeneity in T cell functional potential was largely apparent as T cells initiated clonal expansion. Moreover, by analyzing the fate of single activated T cells ex vivo, we have provided evidence that these early differences resulted in clonal progenies with distinct functional properties. Thus, the early set of T cell-DC interactions in lymph nodes largely contribute to the heterogeneity of T cell responses through the generation of functionally divergent clonal progenies.

CD40 ligand‐expressing recombinant vaccinia virus promotes the generation of CD8+ central memory T cells

“…In the TAA-model (melanoma L27MelanA/Mart-1 [26][27][28][29][30][31][32][33][34][35] ), percentages of antigen-specific CD8 + T cells expanded upon priming with rVV40L or s40L-activated CD14 + monocytes, as evaluated by multimer staining on day 8 (Fig. 4A top), were similar.…”

“…4A top), were similar. However, >45% of L27MelanA/Mart-1 [26][27][28][29][30][31][32][33][34][35] multimer positive CD8 + T cells primed with rVV40L-infected CD14 + monocytes displayed a central memory-like phenotype, whereas APCs treated with s40L recombinant protein promoted the differentiation of a significantly lower fraction of naïve CD8 + T cells into central memory-like cells (31.0%) (Fig. 4A).…”

“…Specific binding was evaluated by flow cytometry (FACScalibur; Becton Dickinson Allschwil, Switzerland). To identify cells bearing antigen-specific TCR, CD8 + T cells were stained with soluble HLA-A0201-peptide, streptavidin R-PE conjugated multimers containing L27Melan-A/MART-1 [26][27][28][29][30][31][32][33][34][35] , vaccinia virus H3L [184][185][186][187][188][189][190][191][192] , HCMVpp65 495-504 , and influenza A MP 58-66 (ProImmune, Oxford, UK). Data were analyzed by FlowJo software (Tree Star, Ashland, OR).…”

“…HLA-A0201-restricted L27Melan-A/MART-1 [26][27][28][29][30][31][32][33][34][35] , vaccinia virus H3L [184][185][186][187][188][189][190][191][192] , HCMV pp65 [495][496][497][498][499][500][501][502][503][504] , and Influenza A MP 58-66 peptides used in this study were provided by PolyPeptide Laboratories (Strasbourg, France). Purified CD14 + cells were incubated for 4h at 37°with individual or pooled peptides at 1 μg/mL final concentration.…”

“…Furthermore, transfer of "in vitro" induced antigen-specific CD8 + T CM warrants a high effectiveness of adoptive immunotherapy treatments against cancer or virus infections [9,10,32,33]. Thus, the induction of T CM cells represents a key clinical priority [34].An important role in the generation of effective memory CD8 + T cells is played by the conditions of the initial stimulation [35] and CD4 + T-cell help has repeatedly been shown to be of essential relevance [17,19,21]. CD8 + T lymphocytes primed in "helpless" conditions might still be able to kill targets expressing appropriate antigens and MHC, and to produce a limited array of cytokines, but they would fail to respond to specific TCR triggering with proliferation and IL-2 production [19].…”