A new MVA ancestor-derived oncolytic vaccinia virus induces immunogenic tumor cell death and robust antitumor immune responses

Vaccinia viruses (VACV) are versatile therapeutic agents and different features of various VACV strains allow for a broad range of therapeutic applications. Modified Vaccinia virus Ankara (MVA) is a particularly altered VACV strain that is highly immunogenic, incapable of replicating in mammalian hosts, and broadly used as a safe vector for vaccination. Alternatively, Western Reserve (WR) or Copenhagen (Cop) are VACV strains that efficiently replicate in cancer cells and therefore are used to develop oncolytic viruses. However, the immune evasion capacity of WR or Cop hinders their ability to elicit antitumor immune responses, which is crucial for efficacy in the clinic. Here, we describe a new VACV strain named Immune-Oncolytic Vaccinia virus Ankara (IOVA), which combines efficient replication in cancer cells with induction of immunogenic tumor cell death (ICD). IOVA was engineered from an MVA ancestor and shows superior cytotoxicity in tumor cells. In addition, the IOVA genome incorporates mutations that lead to massive fusogenesis of tumor cells, which contributes to improved antitumor effects. In syngeneic mouse tumor models, induction of ICD results in robust antitumor immunity directed against tumor neo-epitopes and eradication of large established tumors. These data present IOVA as an improved immunotherapeutic oncolytic vector.

Improving poxvirus-mediated antitumor immune responses by deleting viral cGAMP-specific nuclease

cGAMP-specific nucleases (poxins) are a recently described family of proteins dedicated to obstructing cyclic GMP-AMP synthase signaling (cGAS), an important sensor triggered by cytoplasmic viral replication that activates type I interferon (IFN) production. The B2R gene of vaccinia viruses (VACV) codes for one of these nucleases. Here, we evaluated the effects of inactivating the VACV B2 nuclease in the context of an oncolytic VACV. VACV are widely used as anti-cancer vectors due to their capacity to activate immune responses directed against tumor antigens. We aimed to elicit robust antitumor immunity by preventing viral inactivation of the cGAS/STING/IRF3 pathway after infection of cancer cells. Activation of such a pathway is associated with a dominant T helper 1 (Th1) cell differentiation of the response, which benefits antitumor outcomes. Deletion of the B2R gene resulted in enhanced IRF3 phosphorylation and type I IFN expression after infection of tumor cells, while effective VACV replication remained unimpaired, both in vitro and in vivo. In syngeneic mouse tumor models, the absence of the VACV cGAMP-specific nuclease translated into improved antitumor activity, which was associated with antitumor immunity directed against tumor epitopes.

Activation of interferon regulatory factor 3 by replication-competent vaccinia viruses improves antitumor efficacy mediated by T cell responses

Recently, oncolytic vaccinia viruses (VACVs) have shown their potential to provide for clinically effective cancer treatments. The reason for this clinical usefulness is not only the direct destruction of infected cancer cells but also activation of immune responses directed against tumor antigens. For eliciting a robust antitumor immunity, a dominant T helper 1 (Th1) cell differentiation of the response is preferred, and such polarization can be achieved by activating the Toll-like receptor 3 (TLR3)-interferon regulatory factor 3 (IRF3) signaling pathway. However, current VACVs used as oncolytic viruses to date still encode several immune evasion proteins involved in the inhibition of this signaling pathway. By inactivating genes of selected regulatory virus proteins, we aimed for a candidate virus with increased potency to activate cellular antitumor immunity but at the same time with a fully maintained replicative capacity in cancer cells. The removal of up to three key genes (C10L, N2L, and C6L) from VACV did not reduce the strength of viral replication, both in vitro and in vivo, but resulted in the rescue of IRF3 phosphorylation upon infection of cancer cells. In syngeneic mouse tumor models, this activation translated to enhanced cytotoxic T lymphocyte (CTL) responses directed against tumor-associated antigens and neo-epitopes and improved antitumor activity.

Recombinant viruses delivering the necroptosis mediator MLKL induce a potent antitumor immunity in mice

Vaccinia viruses (VACV) are a novel class of immune-oncolytic therapeutics and their mechanism of action is based both on their capacity to replicate selectively in cancer cells and to elicit danger signals that can boost anti-tumor immunity. We recently reported that the intratumor expression of MLKL, a necroptosis inducing factor, generates a protective anti-tumor immunity. Here, we combined both approaches to test the use of VACV to deliver MLKL into the tumor. We generated VACV vectors expressing MLKL and evaluated the effects of MLKL on antitumor efficacy. In vitro infection of cancer cells with MLKL-expressing vectors led to cell death with necroptotic hallmarks. In syngeneic mouse tumor models, VACV expressing MLKL induced an outstanding antitumor activity, which was associated with a robust immunity directed against neo-epitopes. In conclusion, delivery of MLKL by VACV vectors boosts the intrinsic anti-tumor properties of these viral vectors by promoting in situ immunogenic cell death of infected cancer cells.

MO-D-213CD-01: Cartesian Methods for Rapid Time-Resolved MR Angiography

The physics of the MR image formation fundamentally trades off spatial resolution with temporal resolution. Time spent in acquiring data for the second image of a time series can alternatively be spent in sampling higher spatial frequencies for the first image to improve its spatial resolution. Historically this tradeoff has been addressed by making the k-space sampling rate high, such as with very short repetition times, and with methods such as view sharing in which only a portion of k-space is updated from one image to the next in a time series. Over a decade ago the method of parallel acquisition was proposed in which the signals detected by the individual elements comprising a multi-element receiver coil are used to provide further spatial discrimination and reduce acquisition time. These approaches include those based in image space (SENSE) or in k- space (SMASH, GRAPPA). In the last decade these methods have been integrated in contrast-enhanced MRA (CE-MRA) to provide a radical improvement in performance. CE-MRA is an application particularly well suited to these methods. The general desire for MRA images to be three-dimensional allows the use of 2D implementation of parallel acquisition, generally much more robust than 1D implementation. Also, the SNR loss associated with parallel acquisition is tempered in CE-MRA because high, arterial-phase signal is sampled throughout the data acquisition. Cartesian MR data acquisition, performed along a rectilinear sampling pattern in k-space, offers specific advantages in relative ease of implementation of 2D parallel acquisition and in "freezing" the status of the time-varying object at a specific timepoint by use of centric view ordering. This presentation will provide a review of these methods and how they have been effectively developed and integrated within the last decade for improved time-resolved MRA. Cartesian k-space sampling patterns can now be quickly selected on a patient- and anatomy-specific basis for optimum acceleration. Receiver coil arrays have been adapted to allow up to 20× reduction in the number of k-space points sampled for a given spatial resolution. Reconstruction hardware now allows generation of 3D images within only hundreds of msec after data acquisition, permitting real-time generation of diagnostic quality images and their use in interactively guiding other processes.

LEARNING OBJECTIVES

1. Understand recently developed physics techniques which have allowed a 20x improvement in the speed of data acquisition for MR angiography 2. Understand how Cartesian sampling of k-space facilitates the practical and effective implementation of these techniques 3. Show how contemporary implementation of these physics techniques has provided a significant improvement in MRA image quality over the last decade.

Study of CP(N-1) theta-vacua by cluster simulation of SU(N) quantum spin ladders

D-theory provides an alternative lattice regularization of the 2D CP(N-1) quantum field theory in which continuous classical fields emerge from the dimensional reduction of discrete SU(N) quantum spins. Spin ladders consisting of n transversely coupled spin chains lead to a CP(N-1) model with a vacuum angle theta=npi. In D-theory no sign problem arises and an efficient cluster algorithm is used to investigate theta-vacuum effects. At theta=pi there is a first order phase transition with spontaneous breaking of charge conjugation symmetry for CP(N-1) models with N>2.

Chronic post-traumatic radial instability of the metacarpophalangeal joint of the finger. Long-term results of ligament reconstruction

Chronic painful post-traumatic instability of the radial collateral ligament complex of the metacarpophalangeal joint of a finger was treated by tendon graft reconstruction in 24 patients. Seventeen patients (20 joints) were available for a retrospective study at a mean follow-up time of 105 months. Eighty percent of the joints showed excellent or good results, with relief of pain, return of adequate stability, a near normal range of motion and absence of degenerative changes.

[Organization and significance of quality control in recent surgical methods exemplified by 85 consecutive thoracoscopic interventions]

The rapid evolution or rather revolution of minimally invasive surgical techniques is stimulating new technical and clinical innovations. Quality control is of great importance in new areas of technical development where standards do not yet exist. By recording detailed documentation of patient data, indications, operative procedures and initial follow-up we can compare this new technology with the gold standard therapy. This documentation system for thoracoscopic interventions was developed together with the Swiss Group of Laparoscopic and Thoracoscopic Surgeons. This pilot project of 85 consecutive thoracoscopic interventions will demonstrate the acceptability, clinical application and ease with which data can be analyzed. Operative techniques are described in detail: 20 diagnostic interventions with biopsy, 19 apical parietal pleurectomies (+/- resections of bullous lung tissue), 10 therapeutic lung tissue resections, 19 palliative pleurodesis, 5 treatments of pleural empyema, 1 mediastinal tumor resection, 1 esophagectomy, 4 thoracic sympathectomies plus 6 other procedures. Data entry is efficient with mean total time of 10 min for each record. All of the data are entered into a computer database. The possibilities for interpreting and combining this data are presented. The operative techniques can easily be related with history, indications, anesthesia, complications and results. First evaluation of thoracoscopic efficiency is possible. In addition, a detailed analysis of intra- and postoperative complications and of the hospital course can be performed.

[Minimally invasive thoracic surgery]

Surgery of the intrathoracic organs may be performed without compromise of respiratory mechanics considering minimally invasive principles. An analysis of our experience of 373 thoracoscopic interventions reveals that the diverse procedures performed on the pleura (pleurectomy, pleurodesis), on the lung (wedge resection, fistula closure, ligature of parenchymatous leaks) and on other definec anatomical structures such as the sympathetic nerve or the thoracic duct, are effective in the therapy of intrathoracic disease. The most important pathological conditions which may be treated by thoracoscopy are listed. The range of complications (7%) and their causes are discussed. Current developments and innovations are summarized by a short review of the literature.

MRI of brain iron

A prominently decreased signal intensity in the globus pallidum, reticular substantia nigra, red nucleus, and dentate nucleus was routinely noted in 150 consecutive individuals on T2-weighted images (SE 2000/100) using a high field strength (1.5 T)MR system. This MR finding correlated closely with the decreased estimated T2 relaxation times and the sites of preferential accumulation of ferric iron using the Perls staining method on normal postmortem brains. The decreased signal intensity on T2-weighted images thus provides an accurate in vivo map of the normal distribution of brain iron. Perls stain and MR studies in normal brain also confirm an intermediate level of iron distribution in the striatum, and still lower levels in the cerebral gray and white matter. In the white matter, iron concentration is (a) absent in the most posterior portion of the internal capsule and optic radiations, (b) higher in the frontal than occipital regions, and (c) prominent in the subcortical "U" fibers, particularly in the temporal lobe. There is no iron in the brain at birth; it increases progressively with aging. Knowledge of the distribution of brain iron should assist in elucidating normal anatomic structures and in understanding neurodegenerative, demyelinating, and cerebrovascular disorders.

Parkinson plus syndrome: diagnosis using high field MR imaging of brain iron

The distribution of iron in the brain was analyzed using high field strength (1.5 T) magnetic resonance (MR) imaging in 14 healthy control individuals and six patients with Parkinson plus syndromes (multisystem atrophy and progressive supranuclear palsy) who were unresponsive to antiparkinsonian therapy. The normal topographic distribution of iron in the brain as indicated by high field MR images coincided precisely with the distribution of iron in the brain as determined by Perls staining for ferric iron. In Parkinson plus syndromes, there were abnormally increased concentrations of iron (decreased T2 relaxation times) in the putamen, and less prominent increases in the caudate nucleus and lateral pars compacta of the substantia nigra. In high field strength MR images of normal patients, the decreased signal intensity in the globus pallidus is more prominent than that of the putamen. In MR images of patients with Parkinson plus syndromes, the decreased signal intensity of the putamen is more prominent than that of the globus pallidus.

Intracranial intravenous digital subtraction angiography

Intravenous digital subtraction angiography (iDSA) promises to significantly alter the use of conventional cerebral angiography in the workup of neurological patients. Understanding its diagnostic potential and its limitations are important in incorporating this new examination into the diagnostic thought process of neuroradiologic tests. Different image processing techniques such as integration of mask and contrast images promise to improve image quality for neuroradiologic application. At present, iDSA is suitable for the diagnosis and follow-up of vascular lesions (atherosclerosis, aneurysms, arteriovenous malformations, venous sinus occlusion), and tumor (meningioma). Although limited, the spatial resolution of iDSA studies is capable of demonstrating diffuse vascular disease such as arteritis and vasospasm after subarachnoid hemorrhage. In some patients in conjunction with the CT scan, iDSA may prove sufficient as the primary and only diagnostic angiographic test necessary, supplanting conventional angiography.