Circulating Type-1 Anti-Tumor CD4(+) T Cells are Preferentially Pro-Apoptotic in Cancer Patients.

Cancer patients frequently exhibit a deficiency in Type-1 (but not Type-2 or regulatory) CD4(+) T cell responses against tumor-associated antigens (TAA), which may limit protection against disease progression or responsiveness to immunotherapy in these individuals. Since such deficiency was acutely evident in patients with active disease (AD), where chronic stimulation of anti-tumor CD4(+) T cells would be expected and activation-induced cell death may be prevalent, we employed MHC Class II-peptide tetramers to characterize the frequency and apoptotic status of TAA- vs. influenza (FluM1) virus-specific CD4(+) T cells in the peripheral blood of HLA-DR*0401(+) patients with melanoma or renal cell carcinoma.

A novel probe for the non-invasive detection of tumor-associated inflammation.

A novel dual-mode contrast agent was formulated through the addition of an optical near infrared (NIR) probe to a perfluorocarbon (PFC)-based F magnetic resonance imaging (MRI) agent, which labels inflammatory cells in situ. A single PFC-NIR imaging agent enables both a qualitative, rapid optical monitoring of an inflammatory state and a quantitative, detailed and tissue-depth independent magnetic resonance imaging (MRI). The feasibility of in vivo optical imaging of the inflammatory response was demonstrated in a subcutaneous murine breast carcinoma model.

Visualizing arthritic inflammation and therapeutic response by fluorine-19 magnetic resonance imaging (19F MRI).

Background: Non-invasive imaging of inflammation to measure the progression of autoimmune diseases, such as rheumatoid arthritis (RA), and to monitor responses to therapy is critically needed. V-Sense, a perfluorocarbon (PFC) contrast agent that preferentially labels inflammatory cells, which are then recruited out of systemic circulation to sites of inflammation, enables detection by 19F MRI. With no 19F background in the host, detection is highly-specific and can act as a proxy biomarker of the degree of inflammation present.

Intralesional delivery of dendritic cells engineered to express T-bet promotes protective type 1 immunity and the normalization of the tumor microenvironment.

T-bet (Tbx21), a T-box transcription factor, has been previously identified as a master regulator of type 1 T cell polarization. We have also recently shown that the genetic engineering of human dendritic cells (DCs) to express human T-bet cDNA yields type 1-polarizing APCs in vitro (1). In the present study, murine CD11c(+) DCs were transduced with a recombinant adenovirus encoding full-length murine T-bets (DC.

Integrating costimulatory agonists to optimize immune-based cancer therapies.

While immunotherapy for cancer has become increasingly popular, clinical benefits for such approaches remain limited. This is likely due to tumor-associated immune suppression, particularly in the advanced-disease setting. Thus, a major goal of novel immunotherapeutic design has become the coordinate reversal of existing immune dysfunction and promotion of specific tumoricidal T-cell function.

DC expressing transgene Foxp3 are regulatory APC.

Tolerogenic DC and suppressive Foxp3(+) Treg play important roles in preventing autoimmunity and allograft rejection. We report that (adenovirus mediated) ectopic expression of Foxp3 in human DC (i.e.

Ectopic T-bet expression licenses dendritic cells for IL-12-independent priming of type 1 T cells in vitro.

T-bet (TBX21) is a transcription factor required for the optimal development of type 1 immune responses. Although initially characterized for its intrinsic role in T cell functional polarization, endogenous T-bet may also be critical to the licensing of type 1-biasing APCs. Here, we investigated whether human dendritic cells (DC) genetically engineered to express high levels of T-bet (i.

Heat shock protein 90 inhibitor 17-dimethylaminoethylamino-17-demethoxygeldanamycin enhances EphA2+ tumor cell recognition by specific CD8+ T cells.

EphA2, a member of the receptor tyrosine kinase family, is commonly expressed by a broad range of cancer types, where its level of (over)expression correlates with poor clinical outcome. Because tumor cell expressed EphA2 is a nonmutated "self" protein, specific CD8(+) T cells are subject to self-tolerance mechanisms and typically exhibit only moderate-to-low functional avidity, rendering them marginally competent to recognize EphA2(+) tumor cells in vitro or in vivo. We have recently reported that the ability of specific CD8(+) T cells to recognize EphA2(+) tumor cells can be augmented after the cancer cells are pretreated with EphA2 agonists that promote proteasomal degradation and up-regulated expression of EphA2/class I complexes on the tumor cell membrane.

Enhancement in specific CD8+ T cell recognition of EphA2+ tumors in vitro and in vivo after treatment with ligand agonists.

The EphA2 receptor tyrosine kinase is an attractive therapeutic target that is commonly overexpressed on solid tumors, with the degree of overexpression associated with disease progression, metastatic potential, and poor prognosis. Agonistic mAbs or ligand (ephrinA1)-Fc fusion protein are capable of inducing EphA2 internalization and degradation, thereby (at least transiently) eliminating the influence of this oncoprotein. We and others have also shown that EphA2 contains multiple peptide epitopes that can be recognized by effector CD4(+) and CD8(+) T cells isolated from tumor-bearing patients.

CD8+ T-cell responses against hemoglobin-beta prevent solid tumor growth.

Bone marrow-derived dendritic cells engineered using recombinant adenovirus to secrete high levels of IL-12p70 dramatically inhibited the growth of established CMS4 sarcomas in BALB/c mice after intratumoral administration. An analysis of splenic CD8(+) T cells in regressor mice revealed a strong, complex reactivity pattern against high-performance liquid chromatography (HPLC)-resolved peptides isolated by acid elution from single-cell suspensions of surgically resected CMS4 lesions. Mass spectrometry analyses defined two major overlapping peptide species that derive from the murine hemoglobin-beta (HBB) protein within the most stimulatory HPLC fractions.

Interferon-alpha (IFN-alpha)-conditioned DC preferentially stimulate type-1 and limit Treg-type in vitro T-cell responses from RCC patients.

Dendritic cells (DCs) are potent antigen presenting cells and represent attractive candidates for use in novel immunotherapies for patients with renal cell carcinoma (RCC), a disease that has proven refractory to conventional treatment modalities, such as chemotherapy and radiotherapy. Given the perceived need to augment antitumor type-1 immunity (TC1 and Th1) as a therapeutic end point, and the known functional plasticity of DC populations that may display heterogeneous capacity to promote T-cell responses, we sought to identify a preferred DC preparation with this capacity. We compared 2 different preparations of monocyte-derived DC using interferon-alpha (IFN-alpha) (IFN-DC and alphaDC1) with classic DCs "matured" (mDCs) using interleukin-1beta/interleukin-6/tumor necrosis factor-alpha/prostaglandin E2, for their ability to promote autologous TC1 antitumor responses from RCC patients in vitro.

Improving immunotherapy by conditionally enhancing MHC class I presentation of tumor antigen-derived Peptide epitopes.

Tumors represent an altered self cell type that can be recognized by both the host humoral (B cells, antibodies) and cellular (T cells) adaptive immune systems. Because most known tumor-associated antigens (TAA) recognized by T cells represent overexpressed or aberrantly expressed proteins, which are not mutated and to which tolerance has been developed, the anti-TAA T-cell repertoire available to the cancer patient is of moderate-to-low avidity. Specific vaccinations typically amplify the absolute number of such T cells, but may have little consequence on improving their functional avidity, which may fall below a critical threshold required for effective recognition of tumor cells in situ.

Effect of renal cell carcinomas on the development of type 1 T-cell responses.

Purpose: We reported that in renal cell carcinoma patients with active disease, T-cell reactions to the tumor-associated antigens MAGE-6 and EphA2 are highly skewed toward TH2-type cytokine responses [interleukin (IL) 5]. Herein, we determined whether tumor-derived products, including gangliosides isolated from renal cell carcinoma patients, participate in the down-regulation of type 1 T-cell responses.

Experimental Design: T cells from healthy volunteers or renal cell carcinoma patients were cultured in the presence and absence of supernatants derived from renal cell carcinoma explants or with gangliosides isolated from those tumor supernatants.