CD20-targeted measles virus shows high oncolytic specificity in clinical samples from lymphoma patients independent of prior rituximab therapy.

New therapeutic modalities for B-cell non-Hodgkin's lymphomas (B-NHL) are needed, especially for relapsing and aggressive subtypes. Toward this end, we previously generated a fully CD20-targeted and armed measles virus, and tested its efficacy in a xenograft model of mantle cell lymphoma (MCL). Here, we quantify its spread in peripheral blood mononuclear cells and/or tissue of patients with different histological subtypes of B-NHL, including splenic marginal zone lymphoma (SMZL). CD20-targeted MV efficiently infects lymphoma cells from SMZL and MCL while sparing most cells in the CD20-negative population, in contrast to the parental vaccine-lineage MV, which infects CD20-positive and CD20-negative cells equally. Rituximab therapy (4-8 months before relapse) did not interfere with the infectivity and specificity of MV(green)H(blind)antiCD20 in patient lymphoma samples. Thus, CD20-targeted oncolytic virotherapy is likely to be effective after previous antiCD20 therapy.

Mantle cell lymphoma salvage regimen: synergy between a reprogrammed oncolytic virus and two chemotherapeutics.

Measles virus (MV)-PNP H(blind)antiCD20 is a CD20-targeted and prodrug convertase-armed MV that temporarily controls growth of lymphoma xenografts in severe combined immunodeficiency (SCID) mice in combination with fludarabine phosphate (fludarabine). Herein, we examine the replication of this targeted virus and of a vaccine-lineage MV in disease bulks and circulating cells from mantle cell lymphoma (MCL) patients, and show that only the targeted virus is specific for CD20-expressing cells. We then assessed the efficacy of different regimens of administration of this virus in combination with fludarabine and cyclophosphamide (CPA) in an MCL xenograft model. We show that CPA administration before the beginning of virus treatment enhances oncolytic efficacy, likely through temporary immunosuppression. An interval of 1 week between intravenous virus administration and fludarabine treatment further enhanced oncolysis, by synchronizing maximum prodrug convertase expression with fludarabine availability. Finally, three 23-day courses of triple sequential treatment with CPA, virus and fludarabine treatment resulted in complete regression of the xenografts. Secondary disease symptoms interfered with survival, but average survival times increased from 22 to 77 days. These studies document a reprogrammed oncolytic virus, consolidating the effects of two chemotherapeutics, a concept well suited for a phase I clinical trial for MCL patients for whom conventional therapies have failed.

Human Hendra virus infection causes acute and relapsing encephalitis.

AIM: To study the pathology of two cases of human Hendra virus infection, one with no clinical encephalitis and one with relapsing encephalitis. METHODS: Autopsy tissues were investigated by light microscopy, immunohistochemistry and in situ hybridization. RESULTS: In the patient with acute pulmonary syndrome but not clinical acute encephalitis, vasculitis was found in the brain, lung, heart and kidney. Occasionally, viral antigens were demonstrated in vascular walls but multinucleated endothelial syncytia were absent. In the lung, there was severe inflammation, necrosis and viral antigens in type II pneumocytes and macrophages. The rare kidney glomerulus showed inflammation and viral antigens in capillary walls and podocytes. Discrete necrotic/vacuolar plaques in the brain parenchyma were associated with antigens and viral RNA. Brain inflammation was mild although CD68(+) microglia/macrophages were significantly increased. Cytoplasmic viral inclusions and antigens and viral RNA in neurones and ependyma suggested viral replication. In the case of relapsing encephalitis, there was severe widespread meningoencephalitis characterized by neuronal loss, macrophages and other inflammatory cells, reactive blood vessels and perivascular cuffing. Antigens and viral RNA were mainly found in neurones. Vasculitis was absent in all the tissues examined. CONCLUSIONS: The case of acute Hendra virus infection demonstrated evidence of systemic infection and acute encephalitis. The case of relapsing Hendra virus encephalitis showed no signs of extraneural infection but in the brain, extensive inflammation and infected neurones were observed. Hendra virus can cause acute and relapsing encephalitis and the findings suggest that the pathology and pathogenesis are similar to Nipah virus infection.

Viral morphogenesis and morphological changes in human neuronal cells following Tioman and Menangle virus infection.

Tioman virus (TioPV) and Menangle virus (MenPV) are two antigenically and genetically related paramyxoviruses (genus: Rubulavirus, family: Paramyxoviridae) isolated from Peninsular Malaysia (2001) and Australia (1997), respectively. Both viruses are potential zoonotic agents. In the present study, the infectivity, growth kinetics, morphology and morphogenesis of these two paramyxoviruses in a human neuronal cell (SK-N-SH) line were investigated. Sub-confluent SK-N-SH cells were infected with TioPV and MenPV at similar multiplicity of infection. These cells were examined by conventional and immunoelectron microscopy, and virus titres in the supernatants were assayed. Syncytia were observed for both infections in SK-N-SH cells and were more pronounced during the early stages of TioPV infection. The TioPV titre increased consistently (10(1)) every 12 h after infection. In MenPV-infected cells, cellular material was frequently observed within budding virions, and microfilaments and microtubules were abundant. Viral budding was common, and extracellular MenPVs tended to be more pleomorphic compared to TioPVs, which appeared to be more spherical in appearance. The MenPV cytoplasmic viral inclusion appeared to be comparatively smaller, loose and interspersed with randomly scattered circle-like particles, whereas huge tubule-like cytoplasmic inclusions were observed in TioPV-infected cells. Both viruses also displayed different cellular pathology in the SK-N-SH cells. The intracellular ultrastructural characteristics of these two viruses in infected neuronal cells may allow them to be differentiated by electron microscopy.