New and emerging therapeutic options for malignant pleural mesothelioma: review of early clinical trials.

Malignant pleural mesothelioma (MPM) is a rare tumor that is challenging to control. Despite some benefit from using the multimodality-approach (surgery, combination chemotherapy and radiation), survival remains poor. However, current research produced a list of potential therapies.

Immunotherapy for malignant pleural mesothelioma. Current status and future prospects.

Malignant pleural mesothelioma (MPM) is a rare malignancy of the pleura that is frequently resistant to conventional therapies. Immunotherapy is a promising investigational approach for MPM that has shown some evidence of clinical benefit in select patients. However, tumor-induced immunosuppression is likely a major impediment to achieving optimal clinical responses to immunotherapeutic intervention.

TLR-9 signaling and TCR stimulation co-regulate CD8(+) T cell-associated PD-1 expression.

Elevated Programmed Death-1 (PD-1) expression can inhibit T cell activity and is a potential barrier to achieving persisting and optimal immunity via therapeutic vaccination. Using a direct lymph node-targeted vaccination procedure that enabled uncoupling of synthetic peptide (signal 1, TCR-mediated) and adjuvant (signal 2, non-TCR-mediated), we evaluated the impact of varied doses of Toll-like receptor (TLR)-9 ligand CpG oligodeoxynucleotide (ODN) adjuvant on epitope-specific CD8(+) T cell-associated PD-1 expression. Peptide vaccination without adjuvant yielded CD8(+) T cells with significantly elevated PD-1 expression.

Enhancing DNA vaccination by sequential injection of lymph nodes with plasmid vectors and peptides.

DNA vaccines or peptides are capable of inducing specific immunity; however, their translation to the clinic has generally been problematic, primarily due to the reduced magnitude of immune response and poor pharmacokinetics. Herein, we demonstrate that a novel immunization strategy, encompassing sequential exposure of the lymph node milieu to plasmid and peptide in a heterologous prime-boost fashion, results in considerable MHC class I-restricted immunity in mice. Plasmid-primed antigen expression was essential for the generation of a population of central memory T cells, expressing CD62L and low in PD-1, with substantial capability to expand and differentiate to peripheral memory and effector cells, following subsequent exposure to peptide.

Programmed death-1 blockade enhances expansion and functional capacity of human melanoma antigen-specific CTLs.

Negative co-stimulatory signaling mediated via cell surface programmed death (PD)-1 expression modulates T and B cell activation and is involved in maintaining peripheral tolerance. In this study, we examined the effects of a fully human PD-1-abrogating antibody on the in vitro expansion and function of human vaccine-induced CD8+ T cells (CTLs) specific for the melanoma-associated antigens glycoprotein 100 (gp100) and melanoma antigen recognized by T cells (MART)-1. PD-1 blockade during peptide stimulation augmented the absolute numbers of CD3+, CD4+, CD8+ and gp100/MART-1 MHC:peptide tetramer+ CTLs.