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Oncolytic viruses (OVs) are selected or designed to eliminate malignancies by direct infection and lysis of cancer cells. In contrast to this concept of direct tumor lysis by viral infection, we observed that a significant portion of the in vivo tumor killing activity of two OVs, vesicular stomatitis virus (VSV) and vaccinia virus is caused by indirect killing of uninfected tumor cells. Shortly after administering the oncolytic virus we observed limited virus infection, coincident with a loss of blood flow to the interior of the tumor that correlated with induction of apoptosis in tumor cells. Transcript profiling of tumors showed that virus infection resulted in a dramatic transcriptional activation of pro-inflammatory genes including the neutrophil chemoattractants CXCL1 and CXCL5. Immunohistochemical examination of infected tumors revealed infiltration by neutrophils correlating with chemokine induction. Depletion of neutrophils in animals prior to VSV administration eliminated uninfected tumor cell apoptosis and permitted more extensive replication and spreading of the virus throughout the tumor. Taken all together, these results indicate that targeted recruitment of neutrophils to infected tumor beds enhances the killing of malignant cells. We propose that activation of inflammatory cells can be used for enhancing the effectiveness of oncolytic virus therapeutics, and that this approach should influence the planning of therapeutic doses.

Oncolytic viruses constitute a promising therapy against malignant gliomas (MGs). However, virus-induced type I IFN greatly limits its clinical application. The kinase mammalian target of rapamycin (mTOR) stimulates type I IFN production via phosphorylation of its effector proteins, 4E-BPs and S6Ks. Here we show that mouse embryonic fibroblasts and mice lacking S6K1 and S6K2 are more susceptible to vesicular stomatitis virus (VSV) infection than their WT counterparts as a result of an impaired type I IFN response. We used this knowledge to employ a pharmacoviral approach to treat MGs. The highly specific inhibitor of mTOR rapamycin, in combination with an IFN-sensitive VSV-mutant strain (VSVΔM⁵¹), dramatically increased the survival of immunocompetent rats bearing MGs. More importantly, VSVΔM⁵¹ selectively killed tumor, but not normal cells, in MG-bearing rats treated with rapamycin. These results demonstrate that reducing type I IFNs through inhibition of mTORC1 is an effective strategy to augment the therapeutic activity of VSVΔM⁵¹.

Oncolytic viruses (OVs) have shown promising clinical activity when administered by direct intratumoral injection. However, natural barriers in the blood, including antibodies and complement, are likely to limit the ability to repeatedly administer OVs by the intravenous route. We demonstrate here that for a prototype of the clinical vaccinia virus based product Pexa-Vec, the neutralizing activity of antibodies elicited by smallpox vaccination, as well as the anamnestic response in hyperimmune virus treated cancer patients, is strictly dependent on the activation of complement. In immunized rats, complement depletion stabilized vaccinia virus in the blood and led to improved delivery to tumors. Complement depletion also enhanced tumor infection when virus was directly injected into tumors in immunized animals. The feasibility and safety of using a complement inhibitor, CP40, in combination with vaccinia virus was tested in cynomolgus macaques. CP40 pretreatment elicited an average 10-fold increase in infectious titer in the blood early after the infusion and prolonged the time during which infectious virus was detectable in the blood of animals with preexisting immunity. Capitalizing on the complement dependence of antivaccinia antibody with adjunct complement inhibitors may increase the infectious dose of oncolytic vaccinia virus delivered to tumors in virus in immune hosts.

Treatment of permissive tumors with the oncolytic virus (OV) VSV-Δ51 leads to a robust antitumor T-cell response, which contributes to efficacy; however, many tumors are not permissive to in vivo treatment with VSV-Δ51. In an attempt to channel the immune stimulatory properties of VSV-Δ51 and broaden the scope of tumors that can be treated by an OV, we have developed a potent oncolytic vaccine platform, consisting of tumor cells infected with VSV-Δ51. We demonstrate that prophylactic immunization with this infected cell vaccine (ICV) protected mice from subsequent tumor challenge, and expression of granulocyte–monocyte colony stimulating factor (GM-CSF) by the virus (VSVgm-ICV) increased efficacy. Immunization with VSVgm-ICV in the VSV-resistant B16-F10 model induced maturation of dendritic and natural killer (NK) cell populations. The challenge tumor is rapidly infiltrated by a large number of interferon γ (IFNγ)-producing T and NK cells. Finally, we demonstrate that this approach is robust enough to control the growth of established tumors. This strategy is broadly applicable because of VSV's extremely broad tropism, allowing nearly all cell types to be infected at high multiplicities of infection in vitro, where the virus replication kinetics outpace the cellular IFN response. It is also personalized to the unique tumor antigen(s) displayed by the cancer cell.

Replicating viruses for the treatment of cancer have a number of advantages over traditional therapeutic modalities. They are highly targeted, self-amplifying, and have the added potential to act as both gene-therapy delivery vehicles and oncolytic agents. Parapoxvirus ovis or Orf virus (ORFV) is the prototypic species of the Parapoxvirus genus, causing a benign disease in its natural ungulate host. ORFV possesses a number of unique properties that make it an ideal viral backbone for the development of a cancer therapeutic: it is safe in humans, has the ability to cause repeat infections even in the presence of antibody, and it induces a potent Th-1-dominated immune response. Here, we show that live replicating ORFV induces an antitumor immune response in multiple syngeneic mouse models of cancer that is mediated largely by the potent activation of both cytokine-secreting, and tumoricidal natural killer (NK) cells. We have also highlighted the clinical potential of the virus by demonstration of human cancer cell oncolysis including efficacy in an A549 xenograft model of cancer.

Histone deacetylase inhibitors (HDACi) can modulate innate antiviral responses and render tumors more susceptible to oncolytic viruses (OVs); however, their effects on adaptive immunity in this context are largely unknown. Our present study reveals an unexpected property of the HDACi MS-275 that enhances viral vector-induced lymphopenia leading to selective depletion of bystander lymphocytes and regulatory T cells while allowing expansion of antigen-specific secondary responses. Coadministration of vaccine plus drug during the boosting phase focuses the immune response on the tumor by suppressing the primary immune response against the vaccine vector and enhancing the secondary response against the tumor antigen. Furthermore, improvement of T cell functionality was evident suggesting that MS-275 can orchestrate a complex array of effects that synergize immunotherapy and viral oncolysis. Surprisingly, while MS-275 dramatically enhanced efficacy, it suppressed autoimmune pathology, profoundly improving the therapeutic index.

Optimal immunosuppressive medication adherence is essential to graft survival. Transplant-TAVIE is a Web-based tailored intervention developed to promote this adherence. The objective of our study was to evaluate the Transplant-TAVIE intervention's acceptability, feasibility, and preliminary efficacy. In a pilot, parallel-group, randomized controlled trial, we randomly assigned a convenience sample of 70 kidney transplant patients on immunosuppressive medication either to an experimental group (Transplant-TAVIE) or to a control group (existing websites). Kidney transplant recipients had to be older than 18 years, be taking immunosuppressant medication, and have access to the internet to participate in this study. Transplant-TAVIE was composed of three interactive Web-based sessions hosted by a virtual nurse. We documented user appreciation of and exposure to the intervention. Furthermore, we assessed medication adherence, medication self-efficacy, intake-related skills, and medication side effects at baseline and 3 and 6 months later. Analyses of variance were used to assess intergroup differences over time. After baseline questionnaire completion, participants were randomly assigned either to Transplant-TAVIE (n=35) or to the websites (n=35) group. All participants had received their kidney graft <1 year to 32 years earlier (mean 6.8 years). Of the experimental group, 54% (19/35) completed the sessions of Transplant-TAVIE. Users found the intervention to be acceptable-33% were extremely satisfied (6/18), 39% were very satisfied (7/18), and 28% were satisfied (5/18). At baseline and over time, both experimental and control groups reported high medication adherence, high medication self-efficacy, and frequent use of skills related to medication intake. No intergroup differences emerged over time. The results of this study support the feasibility and acceptability of Transplant-TAVIE. It could constitute an accessible adjunct in support of existing specialized services.

This large randomized trial showed that, among women in labor who have thick meconium staining of the amniotic fluid, amnioinfusion (infusion of saline into the amniotic cavity) did not reduce the risk of moderate or severe meconium aspiration syndrome, perinatal death, or other major maternal or neonatal morbidity. These data suggest no benefit to amnioinfusion, at least in settings with resources for fetal heart-rate monitoring and resuscitation, as in this trial. Among women in labor who have thick meconium staining of the amniotic fluid, amnioinfusion did not reduce the risk of moderate or severe meconium aspiration syndrome, perinatal death, or other major maternal or neonatal morbidity. Meconium-stained amniotic fluid occurs in 7 to 22 percent of term deliveries, 1 , 2 and the meconium aspiration syndrome complicates 1.7 to 35.8 percent of these deliveries. 3 – 8 The case fatality rate of the meconium aspiration syndrome is reported to range from 5 to 40 percent. 4 , 9 – 11 The meconium aspiration syndrome is believed to result from aspiration of meconium during intrauterine gasping or at the first breath. Prophylactic pharyngeal suctioning and tracheal aspiration have not been shown to reduce the risk of the meconium aspiration syndrome. 4 Amnioinfusion, or transcervical infusion of saline into the amniotic cavity, has been proposed as . . .