CD134 and CD137 primed CD8 T cells mount powerful effector responses upon recall, but even without recall these dual costimulated T cells respond to signal 3 cytokines like IL-12. We searched for alternative signal 3 receptor pathways and found the IL-1 family member IL-36R. While IL-36 alone did not stimulate effector CD8 T cells, in combination with IL-12, or more surprisingly IL-2, induced striking and rapid TCR-independent IFN-γ synthesis. To understand how signal 3 responses functioned in dual costimulated T cells we showed that IL-2 induced IL-36R gene expression in a JAK/STAT dependent manner. These data help delineate a sequential stimulation process where IL-2 conditioning must precede IL-36 for IFN-γ synthesis. Importantly, this responsive state was transient, and functioned only in effector T cells capable of aerobic glycolysis. Specifically, as the effector T cells metabolized glucose and consumed O2, they also retained potential to respond through IL-36R. This suggests that T cells use innate receptor pathways like the IL-36R-axis when programmed for aerobic glycolysis. To explore a function for IL-36R in vivo we showed that dual costimulation therapy reduced B16 melanoma tumor growth while increasing IL-36R gene expression. In sum, cytokine therapy to eliminate tumors may target effector T cells, even outside of TCR specificity, as long as the effectors are in the correct metabolic state.

No abstract

The ability of immune-based cancer therapies to elicit beneficial CD8+ CTL is limited by tolerance pathways that inactivate tumor-specific CD4 helper T cells. A strategy to bypass this problem is to engage tumor-unrelated CD4 helper T cells. Thus, CD4 T cells, regardless of their specificity per se, can boost CD8+ CTL priming so long as the cognate epitopes are linked via presentation on the same dendritic cell. Here, we assessed the therapeutic impact of engaging tumor-unrelated CD4 T cells during dual costimulation with CD134 plus CD137 that not only provide help via the above-mentioned classical linked pathway, but also provide non-linked help that facilitates CTL function in T cells not directly responding to cognate antigen. We found that engagement of tumor-unrelated CD4 helper T cells dramatically boosted the ability of dual costimulation to control the growth of established B16 melanomas. Surprisingly, this effect depended upon a CD134-dependent component that was extrinsic to the tumor-unrelated CD4 T cells, suggesting that the dual-costimulated helper cells are themselves helped by a CD134+ cell(s). Nevertheless, the delivery of therapeutic help tracked with an increased frequency of tumor-infiltrating granzyme B+ effector CD8 T cells and a reciprocal decrease in Foxp3+CD4+ cell frequency. Notably, the tumor-unrelated CD4 helper T cells also infiltrated the tumors, and their deletion several days following initial T cell priming negated their therapeutic impact. Taken together, dual costimulation programs tumor-unrelated CD4 T cells to deliver therapeutic help during both the priming and effector stages of the anti-tumor response.

No abstract

Acute respiratory distress syndrome (ARDS) is a serious, often fatal condition without available pharmacotherapy. Although the role of innate cells in ARDS has been studied extensively, emerging evidence suggests that T cells may be involved in disease etiology. enterotoxins are potent T-cell mitogens capable of triggering life-threatening shock. We demonstrate that 2 days after inhalation of enterotoxin A, mice developed T cell-mediated increases in vascular permeability, as well as expression of injury markers and caspases in the lung. Pulmonary endothelial cells underwent sequential phenotypic changes marked by rapid activation coinciding with inflammatory events secondary to T-cell priming, followed by reductions in endothelial cell number juxtaposing simultaneous T-cell expansion and cytotoxic differentiation. Although initial T-cell activation influenced the extent of lung injury, CD54 (ICAM-1) blocking antibody administered well after enterotoxin exposure substantially attenuated pulmonary barrier damage. Thus CD54-targeted therapy may be a promising candidate for further exploration into its potential utility in treating ARDS patients.

Host anti-tumor immunity can be hindered by various mechanisms present within the tumor microenvironment, including the actions of myeloid-derived suppressor cells (MDSCs). We investigated the role of the CCR2/MCP-1 pathway in MDSC-associated tumor progression in murine lung cancer models. Phenotypic profiling revealed maximal expression of CCR2 by tumor-resident MDSCs, and MCP-1 by transplanted TC1 tumor cells, respectively. Use of CCR2-knockout (CCR2-KO) mice showed dependence of tumor growth on CCR2 signaling. Tumors in CCR2-KO mice had fewer CCR2low MDSCs, CD4 T cells and Tregs than WT mice, and increased infiltration by CD8 T cells producing IFN-γ and granzyme-B. Effects were MDSC specific, since WT and CCR2-KO conventional T (Tcon) cells had comparable proliferation and production of inflammatory cytokines, and suppressive functions of WT and CCR2-KO Foxp3+ Treg cells were also similar. We used a thioglycolate-induced peritonitis model to demonstrate a role for CCR2/MCP-1 in trafficking of CCR2+ cells to an inflammatory site, and showed the ability of a CCR2 antagonist to inhibit such trafficking. Use of this CCR2 antagonist promoted anti-tumor immunity and limited tumor growth. In summary, tumor cells are the prime source of MCP-1 that promotes MDSC recruitment, and our genetic and pharmacologic data demonstrate that CCR2 targeting may be an important component of cancer immunotherapy.

Agonists to the TNF/TNFR costimulatory receptors CD134 (OX40) and CD137 (4-1BB) elicit antitumor immunity. Dual costimulation with anti-CD134 plus anti-CD137 is particularly potent because it programs cytotoxic potential in CD8 and CD4 T cells. Cytotoxicity in dual-costimulated CD4 T cells depends on the T-box transcription factor eomesodermin (Eomes), which we report is induced via a mechanism that does not rely on IL-2, in contrast to CD8 CTL, but rather depends on the CD8 T cell lineage commitment transcription factor Runx3, which supports Eomes expression in mature CD8 CTLs. Further, Eomes and Runx3 were indispensable for dual-costimulated CD4 T cells to mediate antitumor activity in an aggressive melanoma model. Runx3 is also known to be expressed in standard CD4 Th1 cells where it fosters IFN-γ expression; however, the CD4 T cell lineage commitment factor ThPOK represses transcription of and other CD8 lineage genes, such as Hence, CD4 T cells can differentiate into Eomes cytotoxic CD4CD8 double-positive T cells by terminating ThPOK expression. In contrast, dual-costimulated CD4 T cells express Eomes, despite the continued expression of ThPOK and the absence of CD8α, indicating that is selectively released from ThPOK repression. Finally, although Eomes was induced by CD137 agonist, but not CD134 agonist, administered individually, CD137 agonist failed to induce CD134 CD4 T cells to express Eomes or Runx3, indicating that both costimulatory pathways are required for cytotoxic Th1 programming, even when only CD137 is intentionally engaged with a therapeutic agonist.

Fasciotomy incisions lead to large, unsightly, chronic wounds after surgical intervention. Classic management was to use split-thickness skin grafts, but this leads to insensate skin with reports that as many as 23% of patients are dissatisfied by the appearance of the wound. Since no skin loss has occurred with the fasciotomy incision, utilizing the dermal properties of creep, stress relaxation and load cycling, closure can be achieved in a better way. We describe using dermotaxis for skin edge approximation that is done using inexpensive equipment available readily in any standard operating room. Twenty-five patients had fasciotomy wounds closed either by dermotaxis or a loop suture technique with the inclusion criteria being closed fractures, no concomitant skin loss, fracture-related compartment syndrome and fasciotomy performed within 36 h. The fasciotomy incision was closed in a single stage by loop suture technique or gradually by dermotaxis once the oedema had settled between 3 and 5 days. Results were graded as excellent if approximation could be achieved, good if sutures had to be applied for protective care and poor if wounds needed to be skin-grafted. In the dermotaxis group, results were excellent in 15, good in 8 and poor in 2 cases. In the loop suture technique group, results were excellent in 20, good in 4 and poor in 1 case. Dermal apposition using inexpensive, readily available equipment is an alternative method for closure of fasciotomy wounds. If limb oedema has settled sufficiently, closure using a loop suture can be done in a single stage. If the limb remains oedematous, gradual closure can be done using dermotaxis.