14 research outputs found
Elimination of Metastatic Melanoma Using Gold Nanoshell-Enabled Photothermal Therapy and Adoptive T Cell Transfer
Ablative treatments such as photothermal therapy (PTT) are attractive anticancer strategies because they debulk accessible
tumor sites while simultaneously priming antitumor immune responses. However, the immune response following thermal
ablation is often insufficient to treat metastatic disease. Here we demonstrate that PTT induces the expression of
proinflammatory cytokines and chemokines and promotes the maturation of dendritic cells within tumor-draining lymph
nodes, thereby priming antitumor T cell responses. Unexpectedly, however, these immunomodulatory effects were not
beneficial to overall antitumor immunity. We found that PTT promoted the infiltration of secondary tumor sites by
CD11b+Ly-6G/C+ myeloid-derived suppressor cells, consequently failing to slow the growth of poorly immunogenic B16-F10
tumors and enhancing the growth of distant lung metastases. To exploit the beneficial effects of PTT activity against local
tumors and on antitumor immunity whilst avoiding the adverse consequences, we adoptively transferred gp100-specific
pmel T cells following PTT. The combination of local control by PTT and systemic antitumor immune reactivity provided by
adoptively transferred T cells prevented primary tumor recurrence post-ablation, inhibited tumor growth at distant sites,
and abrogated the outgrowth of lung metastases. Hence, the combination of PTT and systemic immunotherapy prevented
the adverse effects of PTT on metastatic tumor growth and optimized overall tumor control
IRAK-M Expression Limits Dendritic Cell Activation and Proinflammatory Cytokine Production in Response to <i>Helicobacter pylori</i>
<div><p><i>Helicobacter pylori</i> (<i>H. pylori</i>) infects the gastric mucosa and persists for the life of the host. Bacterial persistence may be due to the induction of regulatory T cells (T<sub>regs</sub>) whichmay have protective effects against other diseases such as asthma. It has been shown that <i>H. pylori</i> modulates the T cell response through dendritic cell reprogramming but the molecular pathways involved are relatively unknown. The goal of this study was to identify critical elements of dendritic cell (DC) activation and evaluate potential influence on immune activation. Microarray analysis was used to demonstrate limited gene expression changes in <i>H. pylori</i> stimulated bone marrow derived DCs (BMDCs) compared to the BMDCs stimulated with E. coli. IRAK-M, a negative regulator of TLR signaling, was upregulated and we selectedit for investigation of its role in modulating the DC and T cell responses. IRAK-M<sup>−/−</sup> and wild type BMDC were compared for their response to <i>H. pylori</i>. Cells lacking IRAK-M produced significantly greater amounts of proinflammatory MIP-2 and reduced amounts of immunomodulatory IL-10 than wild type BMDC. IRAK-M<sup>−/−</sup> cells also demonstrated increased MHC II expression upon activation. However, IRAK-M<sup>−/−</sup> BMDCs were comparable to wild type BMDCs in inducing T-helper 17 (T<sub>H</sub>17) and T<sub>reg</sub> responses as demonstrated in vitro using BMDC CD4+ T cells co-culture assays,and in vivo though the adoptive transfer of CD4<sup>+</sup> FoxP3-GFP T cells into <i>H. pylori</i> infected IRAK-M<sup>−/−</sup> mice. These results suggest that <i>H. pylori</i> infection leads to the upregulation of anti-inflammatory molecules like IRAK-M and that IRAK-M has a direct impact on innate functions in DCs such as cytokine and costimulation molecule upregulation but may not affect T cell skewing.</p></div