The TLR7/8 agonist, Resiquimod has been used as an immune adjuvant in cancer vaccines. We evaluated the safety and immunogenicity of the cancer testis antigen NY-ESO-1 given in combination with Montanide with or without Resiquimod in high-risk melanoma patients. In Part I of the study, patients received 100ug full length NY-ESO-1 protein emulsified in 1.25mL Montanide (day 1) followed by topical application of 1000mg of 0.2% Resiquimod gel on days 1 and 3 (Cohort 1) versus days 1, 3, and 5 (Cohort 2) of a 21 day cycle. In Part II, patients were randomized to receive 100ug NY-ESO-1 protein plus Montanide (day 1) followed by topical application of placebo gel (Arm-A; N=8) or 1000mg of 0.2% Resiquimod gel (Arm-B; N=12) using the dosing regimen established in Part I. The vaccine regimens were generally well-tolerated. NY-ESO-1-specific humoral responses were induced or boosted in all patients, many of whom had high titer antibodies. In Part II, 16 of 20 patients in both arms had NY-ESO-1-specific CD4+ T-cell responses. CD8+ T-cell responses were only seen in 3 of 12 patients in Arm B. Patients with TLR7 SNP rs179008 had a greater likelihood of developing NY-ESO-1-specific CD8+ responses. In conclusion, NY-ESO-1 protein in combination with Montanide with or without topical Resiquimod is safe and induces both antibody and CD4+ T-cell responses in the majority of patients; the small proportion of CD8+ T-cell responses suggests that the addition of topical Resiquimod to Montanide is not sufficient to induce consistent NY-ESO-1-specific CD8+ T-cell responses.

Anticancer vaccination is a promising approach to increase the efficacy of cytotoxic T lymphocyte-associated protein 4 (CTLA-4) and programmed death ligand 1 (PD-L1) checkpoint blockade therapies. However, the landmark FDA registration trial for anti-CTLA-4 therapy (ipilimumab) revealed a complete lack of benefit of adding vaccination with gp100 peptide formulated in incomplete Freund's adjuvant (IFA). Here, using a mouse model of melanoma, we found that gp100 vaccination induced gp100-specific effector T cells (Teffs), which dominantly forced trafficking of anti-CTLA-4-induced, non-gp100-specific Teffs away from the tumor, reducing tumor control. The inflamed vaccination site subsequently also sequestered and destroyed anti-CTLA-4-induced Teffs with specificities for tumor antigens other than gp100, reducing the antitumor efficacy of anti-CTLA-4 therapy. Mechanistically, Teffs at the vaccination site recruited inflammatory monocytes, which in turn attracted additional Teffs in a vicious cycle mediated by IFN-γ, CXCR3, ICAM-1, and CCL2, dependent on IFA formulation. In contrast, nonpersistent vaccine formulations based on dendritic cells, viral vectors, or water-soluble peptides potently synergized with checkpoint blockade of both CTLA-4 and PD-L1 and induced complete tumor regression, including in settings of primary resistance to dual checkpoint blockade. We conclude that cancer vaccine formulation can dominantly determine synergy, or lack thereof, with CTLA-4 and PD-L1 checkpoint blockade therapy for cancer.

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While clinical studies have established that antigen-loaded DC vaccines are safe and promising therapy for tumors, their clinical efficacy remains to be established. The method described below, prepared in accordance with Good Manufacturing Process (GMP) guidelines, is an optimization of the most common ex vivo preparation method for generating large numbers of DCs for clinical studies. Our method utilizes the synthetic TLR 3 agonist Polyinosinic-Polycytidylic Acid-poly-L-lysine Carboxymethylcellulose (Poly-ICLC) to stimulate the DCs. Our previous study established that Poly-ICLC is the most potent individual maturation stimulus for human DCs as assessed by an upregulation of CD83 and CD86, induction of interleukin-12 (IL-12), tumor necrosis factor (TNF), interferon gamma-induced protein 10 (IP-10), interleukmin 1 (IL-1), and type I interferons (IFN), and minimal interleukin 10 (IL-10) production. DCs are differentiated from frozen peripheral blood mononuclear cells (PBMCs) obtained by leukapheresis. PBMCs are isolated by Ficoll gradient centrifugation and frozen in aliquots. On Day 1, PBMCs are thawed and plated onto tissue culture flasks to select for monocytes which adhere to the plastic surface after 1-2 hr incubation at 37 °C in the tissue culture incubator. After incubation, the lymphocytes are washed off and the adherent monocytes are cultured for 5 days in the presence of interleukin-4 (IL-4) and granulocyte macrophage-colony stimulating factor (GM-CSF) to differentiate to immature DCs. On Day 6, immature DCs are pulsed with the keyhole limpet hemocyanin (KLH) protein which serves as a control for the quality of the vaccine and may boost the immunogenicity of the vaccine. The DCs are stimulated to mature, loaded with peptide antigens, and incubated overnight. On Day 7, the cells are washed, and frozen in 1 ml aliquots containing 4-20 x 10(6) cells using a controlled-rate freezer. Lot release testing for the batches of DCs is performed and must meet minimum specifications before they are injected into patients.

Clinical response rates after adoptive cell therapy (ACT) are highly correlated with in vivo persistence of the infused T cells. However, antigen-specific T cells found in tumor sites are often well-differentiated effector cells with limited persistence. Central memory CD8 + T cells, capable of self-renewal, represent desirable ACT products. We report here that exposure to a histone deacetylase inhibitor (HDACi) and IL21 could reprogram differentiated human CD8 + T cells into central memory-like T cells. De-differentiation of CD8 + T cells was initiated by increased H3 acetylation and chromatin accessibility at the CD28 promoter region. This led to IL21-mediated pSTAT3 binding to the CD28 region, and subsequent upregulation of surface CD28 and CD62L (markers of central memory T cells). The reprogrammed cells exhibited enhanced proliferation in response to both IL2 and IL15, and a stable memory-associated transcriptional signature (increased Lef1 and Tcf7). Our findings support the application of IL21 and HDACi for the in vitro generation of highly persistent T cell populations that can augment the efficacy of adoptively transferred T cells.

Studies suggest that conventional cancer therapies given after immunotherapy (IT) can boost antitumor immunity and possibly improve response rates and progression-free survival. We report two cases of metastatic breast cancer with durable complete responses (CRs) after sequential IT and endocrine therapy. Immune analyses of these long-term disease-free breast cancer patients previously treated with imiquimod (IMQ) suggest in-situ vaccination is achieved by topical application of the TLR-7 agonist directly onto tumors. Furthermore, IT-induced antigen-specific T cells were expanded by subsequent endocrine therapy and correlated with response, persisting > 2 years. Our findings therefore suggest that the induction/boosting of polyfunctional tumor antigen-specific T in response to sequential immune endocrine therapy and detected directly ex-vivo can serve as a peripheral blood biomarker for true clinical benefit.Electronic supplementary materialThe online version of this article (doi:10.1186/s40425-014-0032-2) contains supplementary material, which is available to authorized users.

Background: IL-18 gene polymorphisms is shown to be involved in various diseases. This study examines the influence of IL-18 gene polymorphism on the natural course of Hepatitis B Virus (HBV) infection together with the impact of serum levels in Iraqi population for the first time.Methods: A total of 55 patients and similar numbers of healthy controls were recruited in this study. Gene polymorphisms at positions -607C/A and -137G/C of IL-18 were examined using the allele-specific polymerase chain reaction (PCR). Serum levels of IL-18 were determined by an ELISA kit.Results: Three genotypes of IL-18-607C/A (rs1946518) were observed and distributed variably in both patients and controls: CC, CA, and AA with frequencies 41 (82%), 3 (6%), and 6 (12%), in patients and in 44 (88%), 5 (10%), and 1 (2%) in the controls, respectively. The homozygous -607AA mutant genotype, A and C allele frequencies were significantly higher (p=0.043) in patients than the healthy control group (A: 15% and 7%, p=0.04 and C: 85% and 93%, p=0.04, respectively) (OR=2.3445, 95%CI=0.9121-6.0269). The effect of treatment against HBV on genotype and allele frequencies compared with untreated patients revealed that CC and AA genotypes were significantly higher (p=0.04) in treated than untreated patients mirrored results obtained in patients and controls. Three genotypes of IL-18-137G/C (rs187238) were observed in both patients and healthy controls: GG, GC, and CC that appeared in 30 (60%), 18 (36%), and 2 (4%) of HBV infected patients and in 32 (64%), 16 (32%), and 2 (4%) of the control group, respectively. No significant genotype or alleles (G and C) frequencies observed between patients and controls (OR=0.863, 95%CI=0.4485-1.7516). Serum levels of IL-18 was found to be significantly higher in HBV-infected patients compared to the control group. IL-18 levels decreased significantly by various genotypes of both SNPs and this was consistently associated with the mutant genotypes of -137 SNP.Conclusion: IL-18-607AA mutant genotype and C and A alleles were significantly associated with a high risk to HBV infection in Iraqi population, however, the -137 genotypes had no clear impact on the disease and its role as a protective factor needs further investigation. In contrast, the downregulation of the circulating levels of IL-18 in patients was associated with the -137 and -607 mutant genotypes.