Great progress has been made in the field of tumor immunology in the past decade, but optimism about the clinical application of currently available cancer vaccine approaches is based more on surrogate endpoints than on clinical tumor regression. In our cancer vaccine trials of 440 patients, the objective response rate was low (2.6%), and comparable to the results obtained by others. We consider here results in cancer vaccine trials and highlight alternate strategies that mediate cancer regression in preclinical and clinical models.

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Cancer immunotherapy: moving beyond current vaccines.

Tumours express a range of antigens, including self-antigens. Regulatory T cells are crucial for maintaining T-cell tolerance to self-antigens. Regulatory T cells are thought to dampen T-cell immunity to tumour-associated antigens and to be the main obstacle tempering successful immunotherapy and active vaccination. In this Review, I consider the nature and characteristics of regulatory T cells in the tumour microenvironment and their potential multiple suppressive mechanisms. Strategies for therapeutic targeting of regulatory T cells and the effect of regulatory T cells on current immunotherapeutic and vaccine regimens are discussed.

Regulatory T cells, tumour immunity and immunotherapy

Purpose We investigated the combination of lymphodepleting chemotherapy followed by the adoptive transfer of autologous tumor reactive lymphocytes for the treatment of patients with refractory metastatic melanoma. Patients and Methods Thirty-five patients with metastatic melanoma, all but one with disease refractory to treatment with high-dose interleukin (IL) -2 and many with progressive disease after chemotherapy, underwent lymphodepleting conditioning with two days of cyclophosphamide (60 mg/kg) followed by five days of fludarabine (25 mg/m2). On the day following the final dose of fludarabine, all patients received cell infusion with autologous tumor-reactive, rapidly expanded tumor infiltrating lymphocyte cultures and high-dose IL-2 therapy. Results Eighteen (51%) of 35 treated patients experienced objective clinical responses including three ongoing complete responses and 15 partial responses with a mean duration of 11.5 ± 2.2 months. Sites of regression included metastases to lung, liver, lymph nod...

Adoptive Cell Transfer Therapy Following Non-Myeloablative but Lymphodepleting Chemotherapy for the Treatment of Patients With Refractory Metastatic Melanoma

Immunotherapy based on the adoptive transfer of naturally occurring or gene-engineered T cells can mediate tumour regression in patients with metastatic cancer. Here, we discuss progress in the use of adoptively transferred T cells, focusing on how they can mediate tumour cell eradication. Recent advances include more accurate targeting of antigens expressed by tumours and the associated vasculature, and the successful use of gene engineering to re-target T cells before their transfer into the patient. We also describe how new research has helped to identify the particular T cell subsets that can most effectively promote tumour eradication.

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Adoptive immunotherapy for cancer: harnessing the T cell response

T cell differentiation is a progressive process characterized by phenotypic and functional changes. By transferring tumor-specific CD8+ T cells into tumor-bearing mice at various stages of differentiation, we evaluated their efficacy for adoptive immunotherapy. We found that administration of naive and early effector T cells, in combination with active immunization and IL-2, resulted in the eradication of large, established tumors. Despite enhanced in vitro antitumor properties, more-differentiated effector T cells were less effective for in vivo tumor treatment. Several events may underlie this paradoxical phenomenon: (a) downregulation of lymphoid-homing and costimulatory molecules; (b) inability to produce IL-2 and access homeostatic cytokines; and (c) entry into a proapoptotic and replicative senescent state. While the progressive acquisition of terminal effector properties is characterized by pronounced in vitro tumor killing, in vivo T cell activation, proliferation, and survival are progressively impaired. These findings suggest that the current methodology for selecting T cells for transfer is inadequate and provide new criteria for the generation and the screening of optimal lymphocyte populations for adoptive immunotherapy.

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Acquisition of full effector function in vitro paradoxically impairs the in vivo antitumor efficacy of adoptively transferred CD8+ T cells

IL-15 and IL-2 possess similar properties, including the ability to induce T cell proliferation. However, whereas IL-2 can promote apoptosis and limit CD8+ memory T cell survival and proliferation, IL-15 helps maintain a memory CD8+ T cell population and can inhibit apoptosis. We sought to determine whether IL-15 could enhance the in vivo function of tumor/self-reactive CD8+ T cells by using a T cell receptor transgenic mouse (pmel-1) whose CD8+ T cells recognize an epitope derived from the self/melanoma antigen gp100. By removing endogenous IL-15 by using tumor-bearing IL-15 knockout hosts or supplementing IL-15 by means of exogenous administration, as a component of culture media or as a transgene expressed by adoptively transferred T cells, we demonstrate that IL-15 can improve the in vivo antitumor activity of adoptively transferred CD8+ T cells. These results provide several avenues for improving adoptive immunotherapy of cancer in patients.

https://www.pnas.org/content/pnas/101/7/1969.full.pdf

IL-15 enhances the in vivo antitumor activity of tumor-reactive CD8+ T Cells

Scar formation, with persistent alteration of the normal tissue structure, is an undesirable and significant result of both wound healing and fibrosing disorders. There are few strategies to prevent or to treat scarring. The transforming growth factor beta (TGF-β) superfamily is an important mediator of tissue repair. Each TGF-β isoform may exert a different effect on wound healing, which may be context-dependent. In particular, TGF-β1 may mediate fibrosis in adults' wounds, while TGF-β3 may promote scarless healing in the fetus and reduced scarring in adults. Thus, TGF-β3 may offer a scar-reducing therapy for acute and chronic wounds and fibrosing disorders.

Transforming growth factor beta (TGF-β) isoforms in wound healing and fibrosis.

Nitric oxide-producing myeloid-derived suppressor cells inhibit vascular E-selectin expression in human squamous cell carcinomas.

Cutaneous Crohn disease (CD) affecting the vulva, perineum, and perianal skin, is a rare entity, which may accompany or precede gastrointestinal CD. Vulvar involvement, if untreated, may ultimately require extensive surgery including vulvectomy to gain control of the disease. Both gastrointestinal and cutaneous CD respond to biologics, which block TNF. In addition, ustekinumab, which targets both IL-12 and IL-23 cytokines, is effective in patients with gastrointestinal CD who fail TNF blockade. However, it is unclear if ustekinumab is effective for cutaneous CD. Herein we present a patient with cutaneous CD affecting the vulva and perianal skin, which, at seven months, had a marked response to ustekinumab administered at higher doses than typically used for psoriasis.

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Ustekinumab for treatment of cutaneous Crohn's disease.

This issue provides a clinical overview of Common Cutaneous Parasites focusing on prevention, diagnosis, treatment, practice improvement, and patient information. The content of In the Clinic is dr...

Michael K. Lichtman

Papers

IL-15 enhances the in vivo antitumor activity of tumor-reactive CD8+ T Cells

Transforming growth factor beta (TGF-β) isoforms in wound healing and fibrosis.

Nitric oxide-producing myeloid-derived suppressor cells inhibit vascular E-selectin expression in human squamous cell carcinomas.

Ustekinumab for treatment of cutaneous Crohn's disease.

Common Cutaneous Parasites