Efficient loading of dendritic cells following cryo and radiofrequency ablation in combination with immune modulation induces anti-tumour immunity

Dendritic cells (DC) are professional antigen-presenting cells that play a pivotal role in the induction of immunity. Ex vivo-generated, tumour antigen-loaded mature DC are currently exploited as cancer vaccines in clinical studies. However, antigen loading and maturation of DC directly in vivo would greatly facilitate the application of DC-based vaccines. We formerly showed in murine models that radiofrequency-mediated tumour destruction can provide an antigen source for the in vivo induction of anti-tumour immunity, and we explored the role of DC herein. In this paper we evaluate radiofrequency and cryo ablation for their ability to provide an antigen source for DC and compare this with an ex vivo-loaded DC vaccine. The data obtained with model antigens demonstrate that upon tumour destruction by radiofrequency ablation, up to 7% of the total draining lymph node (LN) DC contained antigen, whereas only few DC from the conventional vaccine reached the LN. Interestingly, following cryo ablation the amount of antigen-loaded DC is almost doubled. Analysis of surface markers revealed that both destruction methods were able to induce DC maturation. Finally, we show that in situ tumour ablation can be efficiently combined with immune modulation by anti-CTLA-4 antibodies or regulatory T-cell depletion. These combination treatments protected mice from the outgrowth of tumour challenges, and led to in vivo enhancement of tumour-specific T-cell numbers, which produced more IFN-γ upon activation. Therefore, in situ tumour destruction in combination with immune modulation creates a unique, ‘in situ DC-vaccine' that is readily applicable in the clinic without prior knowledge of tumour antigens

CD25-Treg-depleting antibodies preserving IL-2 signaling on effector T cells enhance effector activation and antitumor immunity.

Intratumoral regulatory T cell (Treg) abundance associates with diminished anti-tumor immunity and poor prognosis in human cancers. Recent work demonstrates that CD25, the high affinity receptor subunit for IL-2, is a selective target for Treg depletion in mouse and human malignancies; however, anti-human CD25 antibodies have failed to deliver clinical responses against solid tumors due to bystander IL-2 receptor signaling blockade on effector T cells, which limits their anti-tumor activity. Here we demonstrate potent single-agent activity of anti-CD25 antibodies optimized to deplete Tregs whilst preserving IL-2-STAT5 signaling on effector T cells, and demonstrate synergy with immune checkpoint blockade in vivo. Pre-clinical evaluation of an anti-human CD25 (RG6292) antibody with equivalent features demonstrates, in both non-human primates and humanized mouse models, efficient Treg depletion with no overt immune-related toxicities. Our data supports the clinical development of RG6292 and evaluation of novel combination therapies incorporating non-IL-2 blocking anti-CD25 antibodies in clinical studies

Gut Microbiota Is a Key Modulator of Insulin Resistance in TLR 2 Knockout Mice

A genetic and pharmacological approach reveals novel insights into how changes in gut microbiota can subvert genetically predetermined phenotypes from lean to obese

Treatment of disseminated ocular melanoma with sequential fotemustine, interferon α, and interleukin 2

Malignant melanoma of the uvea is remarkable for purely haematogenous dissemination and its tendency to metastasise to the liver. Although the liver is involved in up to 95% of patients, 50% of these also develop extrahepatic metastases, most often in the lungs, bone, skin, and brain. The only effective treatments reported to date relied on hepatic arterial chemoembolisation or -perfusion. The objective of this study was to establish a therapy protocol addressing patients with both sole liver involvement and systemic disease. Forty-eight patients with metastatic ocular melanoma received fotemustine 100 mg m−2 either as 60-min infusion into the hepatic artery or as 15-min infusion via a peripheral vein, depending on the metastatic sites involved, i.e., restriction to the liver or hepatic together with extrahepatic disease. For the first treatment cycle this infusion was repeated after one week. For all cycles, subsequent to a three week resting period, patients received an immunotherapy consisting of subcutaneous interleukin 2 and interferon α2. Although objective responses were more frequent within the cohort receiving intraarterial fotemustine (21.7 vs 8%), this difference did not translate into a significant benefit in overall survival, i.e., 369 and 349 days, respectively. Of note, this overall survival is much longer than that repeatedly reported for stage IV uveal melanoma not treated with fotemustine, suggesting a therapeutic activity of this cytostatic drug even after systemic administration

FMR1 Genotype with Autoimmunity-Associated Polycystic Ovary-Like Phenotype and Decreased Pregnancy Chance

The FMR1 gene partially appears to control ovarian reserve, with a specific ovarian sub-genotype statistically associated with a polycystic ovary (PCO)- like phenotype. Some forms of PCO have been associated with autoimmunity. We, therefore, investigated in multiple regression analyses associations of ovary-specific FMR1 genotypes with autoimmunity and pregnancy chances (with in vitro fertilization, IVF) in 339 consecutive infertile women (455 IVF cycles), 75 with PCO-like phenotype, adjusted for age, race/ethnicity, medication dosage and number of oocytes retrieved. Patients included 183 (54.0%) with normal (norm) and 156 (46%) with heterozygous (het) FMR1 genotypes; 133 (39.2%) demonstrated laboratory evidence of autoimmunity: 51.1% of het-norm/low, 38.3% of norm and 24.2% het-norm/high genotype and sub-genotypes demonstrated autoimmunity (p = 0.003). Prevalence of autoimmunity increased further in PCO-like phenotype patients with het-norm/low genotype (83.3%), remained unchanged with norm (34.0%) and decreased in het-norm/high women (10.0%; P<0.0001). Pregnancy rates were significantly higher with norm (38.6%) than het-norm/low (22.2%, p = 0.001). FMR1 sub-genotype het-norm/low is strongly associated with autoimmunity and decreased pregnancy chances in IVF, reaffirming the importance of the distal long arm of the X chromosome (FMR1 maps at Xq27.3) for autoimmunity, ovarian function and, likely, pregnancy chance with IVF

Humanized Mice Recapitulate Key Features of HIV-1 Infection: A Novel Concept Using Long-Acting Anti-Retroviral Drugs for Treating HIV-1

BACKGROUND: Humanized mice generate a lymphoid system of human origin subsequent to transplantation of human CD34+ cells and thus are highly susceptible to HIV infection. Here we examined the efficacy of antiretroviral treatment (ART) when added to food pellets, and of long-acting (LA) antiretroviral compounds, either as monotherapy or in combination. These studies shall be inspiring for establishing a gold standard of ART, which is easy to administer and well supported by the mice, and for subsequent studies such as latency. Furthermore, they should disclose whether viral breakthrough and emergence of resistance occurs similar as in HIV-infected patients when ART is insufficient. METHODS/PRINCIPAL FINDINGS: NOD/shi-scid/γ(c)null (NOG) mice were used in all experimentations. We first performed pharmacokinetic studies of the drugs used, either added to food pellets (AZT, TDF, 3TC, RTV) or in a LA formulation that permitted once weekly subcutaneous administration (TMC278: non-nucleoside reverse transcriptase inhibitor, TMC181: protease inhibitor). A combination of 3TC, TDF and TMC278-LA or 3TC, TDF, TMC278-LA and TMC181-LA suppressed the viral load to undetectable levels in 15/19 (79%) and 14/14 (100%) mice, respectively. In successfully treated mice, subsequent monotherapy with TMC278-LA resulted in viral breakthrough; in contrast, the two LA compounds together prevented viral breakthrough. Resistance mutations matched the mutations most commonly observed in HIV patients failing therapy. Importantly, viral rebound after interruption of ART, presence of HIV DNA in successfully treated mice and in vitro reactivation of early HIV transcripts point to an existing latent HIV reservoir. CONCLUSIONS/SIGNIFICANCE: This report is a unique description of multiple aspects of HIV infection in humanized mice that comprised efficacy testing of various treatment regimens, including LA compounds, resistance mutation analysis as well as viral rebound after treatment interruption. Humanized mice will be highly valuable for exploring the antiviral potency of new compounds or compounds targeting the latent HIV reservoir

Distinct Effects of IL-18 on the Engraftment and Function of Human Effector CD8+ T Cells and Regulatory T Cells

IL-18 has pleotropic effects on the activation of T cells during antigen presentation. We investigated the effects of human IL-18 on the engraftment and function of human T cell subsets in xenograft mouse models. IL-18 enhanced the engraftment of human CD8+ effector T cells and promoted the development of xenogeneic graft versus host disease (GVHD). In marked contrast, IL-18 had reciprocal effects on the engraftment of CD4+CD25+Foxp3+ regulatory T cells (Tregs) in the xenografted mice. Adoptive transfer experiments indicated that IL-18 prevented the suppressive effects of Tregs on the development of xenogeneic GVHD. The IL-18 results were robust as they were observed in two different mouse strains. In addition, the effects of IL-18 were systemic as IL-18 promoted engraftment and persistence of human effector T cells and decreased Tregs in peripheral blood, peritoneal cavity, spleen and liver. In vitro experiments indicated that the expression of the IL-18Rα was induced on both CD4 and CD8 effector T cells and Tregs, and that the duration of expression was less sustained on Tregs. These preclinical data suggest that human IL-18 may have use as an adjuvant for immune reconstitution after cytotoxic therapies, and to augment adoptive immunotherapy, donor leukocyte infusions, and vaccine strategies