Tumor organoid-T-cell coculture systems.

T cells are key players in cancer immunotherapy, but strategies to expand tumor-reactive cells and study their interactions with tumor cells at the level of an individual patient are limited. Here we describe the generation and functional assessment of tumor-reactive T cells based on cocultures of tumor organoids and autologous peripheral blood lymphocytes. The procedure consists of an initial coculture of 2 weeks, in which tumor-reactive T cells are first expanded in the presence of (IFNγ-stimulated) autologous tumor cells. Subsequently, T cells are evaluated for their capacity to carry out effector functions (IFNγ secretion and degranulation) after recognition of tumor cells, and their capacity to kill tumor organoids. This strategy is unique in its use of peripheral blood as a source of tumor-reactive T cells in an antigen-agnostic manner. In 2 weeks, tumor-reactive CD8+ T-cell populations can be obtained from ~33-50% of samples from patients with non-small-cell lung cancer (NSCLC) and microsatellite-instable colorectal cancer (CRC). This enables the establishment of ex vivo test systems for T-cell-based immunotherapy at the level of the individual patient.

Low and variable tumor reactivity of the intratumoral TCR repertoire in human cancers.

Infiltration of human cancers by T cells is generally interpreted as a sign of immune recognition, and there is a growing effort to reactivate dysfunctional T cells at such tumor sites1. However, these efforts only have value if the intratumoral T cell receptor (TCR) repertoire of such cells is intrinsically tumor reactive, and this has not been established in an unbiased manner for most human cancers. To address this issue, we analyzed the intrinsic tumor reactivity of the intratumoral TCR repertoire of CD8+ T cells in ovarian and colorectal cancer-two tumor types for which T cell infiltrates form a positive prognostic marker2,3. Data obtained demonstrate that a capacity to recognize autologous tumor is limited to approximately 10% of intratumoral CD8+ T cells. Furthermore, in two of four patient samples tested, no tumor-reactive TCRs were identified, despite infiltration of their tumors by T cells. These data indicate that the intrinsic capacity of intratumoral T cells to recognize adjacent tumor tissue can be rare and variable, and suggest that clinical efforts to reactivate intratumoral T cells will benefit from approaches that simultaneously increase the quality of the intratumoral TCR repertoire.

Generation of Tumor-Reactive T Cells by Co-culture of Peripheral Blood Lymphocytes and Tumor Organoids.

Cancer immunotherapies have shown substantial clinical activity for a subset of patients with epithelial cancers. Still, technological platforms to study cancer T-cell interactions for individual patients and understand determinants of responsiveness are presently lacking. Here, we establish and validate a platform to induce and analyze tumor-specific T cell responses to epithelial cancers in a personalized manner. We demonstrate that co-cultures of autologous tumor organoids and peripheral blood lymphocytes can be used to enrich tumor-reactive T cells from peripheral blood of patients with mismatch repair-deficient colorectal cancer and non-small-cell lung cancer. Furthermore, we demonstrate that these T cells can be used to assess the efficiency of killing of matched tumor organoids. This platform provides an unbiased strategy for the isolation of tumor-reactive T cells and provides a means by which to assess the sensitivity of tumor cells to T cell-mediated attack at the level of the individual patient.

Targeting of cancer neoantigens with donor-derived T cell receptor repertoires.

Accumulating evidence suggests that clinically efficacious cancer immunotherapies are driven by T cell reactivity against DNA mutation-derived neoantigens. However, among the large number of predicted neoantigens, only a minority is recognized by autologous patient T cells, and strategies to broaden neoantigen-specific T cell responses are therefore attractive. We found that naïve T cell repertoires of healthy blood donors provide a source of neoantigen-specific T cells, responding to 11 of 57 predicted human leukocyte antigen (HLA)-A*02:01-binding epitopes from three patients. Many of the T cell reactivities involved epitopes that in vivo were neglected by patient autologous tumor-infiltrating lymphocytes. Finally, T cells redirected with T cell receptors identified from donor-derived T cells efficiently recognized patient-derived melanoma cells harboring the relevant mutations, providing a rationale for the use of such "outsourced" immune responses in cancer immunotherapy.

Antigen-specific TIL therapy for melanoma: A flexible platform for personalized cancer immunotherapy.

Tumor infiltrating lymphocyte (TIL) therapy has shown objective clinical response rates of 50% in stage IV melanoma patients in a number of clinical trials. Nevertheless, the majority of patients progress either directly upon therapy or after an initial period of tumor control. Recent data have shown that most TIL products that are used for therapy contain only low frequencies of T cells reactive against known melanoma-associated epitopes. Because of this, the development of a technology to create T-cell products that are enriched for reactivity against defined melanoma-associated antigens would seem valuable, both to evaluate the tumoricidal potential of T cells directed against different antigen classes and to potentially increase response rates. Here, we developed and validated a conditional MHC streptamer-based platform for the creation of TIL products with defined antigen reactivities. We have used this platform to successfully enrich both high-frequency (≥1%) and low-frequency (<1%) tumor-specific CD8(+) T-cell populations, and thereby created T-cell products with enhanced tumor recognition potential. Collectively, these data demonstrate that selection of antigen-specific T-cell populations can be used to create defined T-cell products for clinical use. This strategy thus forms a highly flexible platform for the development of antigen-specific cell products for personalized cancer immunotherapy.

Tumor antigens in human cancer control.

The body of evidence that is supporting the role of T cells in human tumor control is substantial and it is now beyond doubt that T cells can be crucial in the clinical response to cancer immunotherapies such as adoptive T cell therapy and checkpoint blockade. This has been proven in particular for melanoma and non-small cell lung cancer. Strikingly, while clinical experience with these therapies is extensive, what these T cells detect on the tumors remains largely unknown. An extensive effort has been put into the characterization of tumor antigens and based on the recent successes of immunotherapies Cancer/Germline, mutated and viral antigens appear rather promising targets for tumor control. Furthermore, it is becoming evident that the most potent antigen in tumor control is highly dependent on the type of malignancy and may also vary even within malignancies.

Effective Clinical Responses in Metastatic Melanoma Patients after Vaccination with Primary Myeloid Dendritic Cells.

PURPOSE: Thus far, dendritic cell (DC)-based immunotherapy of cancer was primarily based on in vitro-generated monocyte-derived DCs, which require extensive in vitro manipulation. Here, we report on a clinical study exploiting primary CD1c(+) myeloid DCs, naturally circulating in the blood. EXPERIMENTAL DESIGN: Fourteen stage IV melanoma patients, without previous systemic treatment for metastatic disease, received autologous CD1c(+) myeloid DCs, activated by only brief (16 hours) ex vivo culture and loaded with tumor-associated antigens of tyrosinase and gp100. RESULTS: Our results show that therapeutic vaccination against melanoma with small amounts (3-10 × 10(6)) of myeloid DCs is feasible and without substantial toxicity. Four of 14 patients showed long-term progression-free survival (12-35 months), which directly correlated with the development of multifunctional CD8(+) T-cell responses in three of these patients. In particular, high CD107a expression, indicative for cytolytic activity, and IFNγ as well as TNFα and CCL4 production was observed. Apparently, these T-cell responses are essential to induce tumor regression and promote long-term survival by stalling tumor growth. CONCLUSIONS: We show that vaccination of metastatic melanoma patients with primary myeloid DCs is feasible and safe and results in induction of effective antitumor immune responses that coincide with improved progression-free survival. Clin Cancer Res; 22(9); 2155-66. ©2015 AACR.

Mismatch Repair-Deficient Cancers Are Targets for Anti-PD-1 Therapy.

Immune checkpoint-blocking therapies have yielded positive clinical data in a series of human malignancies. Recent work from Le and colleagues strongly supports the use of these therapies for mismatch repair-deficient tumors, independent of underlying tumor type. These data suggest the importance of sensing the consequences of DNA damage in cancer immunotherapy.

T cell immunity. Functional heterogeneity of human memory CD4⁺ T cell clones primed by pathogens or vaccines.

Distinct types of CD4(+) T cells protect the host against different classes of pathogens. However, it is unclear whether a given pathogen induces a single type of polarized T cell. By combining antigenic stimulation and T cell receptor deep sequencing, we found that human pathogen- and vaccine-specific T helper 1 (T(H)1), T(H)2, and T(H)17 memory cells have different frequencies but comparable diversity and comprise not only clones polarized toward a single fate, but also clones whose progeny have acquired multiple fates. Single naïve T cells primed by a pathogen in vitro could also give rise to multiple fates. Our results unravel an unexpected degree of interclonal and intraclonal functional heterogeneity of the human T cell response and suggest that polarized responses result from preferential expansion rather than priming.

Anti-CTLA-4 therapy broadens the melanoma-reactive CD8+ T cell response.

Anti-CTLA-4 treatment improves the survival of patients with advanced-stage melanoma. However, although the anti-CTLA-4 antibody ipilimumab is now an approved treatment for patients with metastatic disease, it remains unknown by which mechanism it boosts tumor-specific T cell activity. In particular, it is unclear whether treatment amplifies previously induced T cell responses or whether it induces new tumor-specific T cell reactivities. Using a combination ultraviolet (UV)-induced peptide exchange and peptide-major histocompatibility complex (pMHC) combinatorial coding, we monitored immune reactivity against a panel of 145 melanoma-associated epitopes in a cohort of patients receiving anti-CTLA-4 treatment. Comparison of pre- and posttreatment T cell reactivities in peripheral blood mononuclear cell samples of 40 melanoma patients demonstrated that anti-CTLA-4 treatment induces a significant increase in the number of detectable melanoma-specific CD8 T cell responses (P = 0.0009). In striking contrast, the magnitude of both virus-specific and melanoma-specific T cell responses that were already detected before start of therapy remained unaltered by treatment (P = 0.74). The observation that anti-CTLA-4 treatment induces a significant number of newly detected T cell responses-but only infrequently boosts preexisting immune responses-provides strong evidence for anti-CTLA-4 therapy-enhanced T cell priming as a component of the clinical mode of action.

Acquired and intrinsic resistance in cancer immunotherapy.

A number of immunotherapies, in particular immune checkpoint targeting antibodies and adoptive T-cell therapies, are starting to transform the treatment of advanced cancers. The likelihood to respond to these immunotherapies differs strongly across tumor types, with response rates for checkpoint targeting being the highest in advanced melanoma, renal cell cancer and non-small cell lung cancer. However, also non-responsiveness is observed, indicating the presence of intrinsic resistance or naturally acquired resistance. In addition, a subgroup of patients that do initially respond to immunotherapy will later recur, thereby also pointing towards a role of therapy-induced acquired resistance. Here, we review our current understanding of both intrinsic and acquired resistance mechanisms in cancer immunotherapy, and discuss potential strategies to overcome them.

Lactate dehydrogenase as a selection criterion for ipilimumab treatment in metastatic melanoma.

INTRODUCTION: Ipilimumab, a cytotoxic T lymphocyte-associated antigen-4 blocking antibody, has improved overall survival (OS) in metastatic melanoma in phase III trials. However, about 80 % of patients fail to respond, and no predictive markers for benefit from therapy have been identified. We analysed a 'real world' population of patients treated with ipilimumab to identify markers for treatment benefit. METHODS: Patients with advanced cutaneous melanoma were treated in the Netherlands (NL) and the United Kingdom (UK) with ipilimumab at 3 mg/kg. Baseline characteristics and peripheral blood parameters were assessed, and patients were monitored for the occurrence of adverse events and outcomes. RESULTS: A total of 166 patients were treated in the Netherlands. Best overall response and disease control rates were 17 and 35 %, respectively. Median follow-up was 17.9 months, with a median progression-free survival of 2.9 months. Median OS was 7.5 months, and OS at 1 year was 37.8 % and at 2 years was 22.9 %. In a multivariate model, baseline serum lactate dehydrogenase (LDH) was demonstrated to be the strongest predictive factor for OS. These findings were validated in an independent cohort of 64 patients from the UK. CONCLUSION: In both the NL and UK cohorts, long-term benefit of ipilimumab treatment was unlikely for patients with baseline serum LDH greater than twice the upper limit of normal. In the absence of prospective data, clinicians treating melanoma may wish to consider the data presented here to guide patient selection for ipilimumab therapy.

[Sternoclavicular joint tuberculosis]. / Een zwelling bij de clavicula.

A 24-year old woman presented with an abscess localized at the median side of the right clavicle. There were no clinical signs of tuberculosis and radiological evaluation was normal. PCR-assay on tuberculosis following aspiration of the pus collection was positive for Mycobacterium tuberculosis. She responded well on regular anti-tuberculosis treatment.

A universal strategy for adoptive immunotherapy of cancer through use of a novel T-cell antigen receptor.

Adoptive immunotherapies composed of T cells engineered to express a chimeric antigen receptor (CAR) offer an attractive strategy for treatment of human cancer. However, CARs have a fixed antigen specificity such that only one tumor-associated antigen (TAA) can be targeted, limiting the efficacy that can be achieved because of heterogeneous TAA expression. For this reason, a more generalized and effective application of CAR therapy would benefit from the capability to produce large panels of CARs against many known TAAs. In this study, we show a novel strategy to extend the recognition specificity potential of a bioengineered lymphocyte population, allowing flexible approaches to redirect T cells against various TAAs. Our strategy employs a biotin-binding immune receptor (BBIR) composed of an extracellular-modified avidin linked to an intracellular T-cell signaling domain. BBIR T cells recognized and bound exclusively to cancer cells pretargeted with specific biotinylated molecules. The versatility afforded by BBIRs permitted sequential or simultaneous targeting of a combination of distinct antigens. Together, our findings show that a platform of universal T-cell specificity can significantly extend conventional CAR approaches, permitting the tailored generation of T cells of unlimited antigen specificity for improving the effectiveness of adoptive T-cell immunotherapies for cancer.