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Heatley S.L.,University of Melbourne | Pietra G.,University of Genoa | Lin J.,University of Melbourne | Widjaja J.M.L.,University of Melbourne | And 11 more authors.
Journal of Biological Chemistry

Natural killer (NK) cell recognition of the nonclassical human leukocyte antigen (HLA) molecule HLA-E is dependent on the presentation of a nonamer peptide derived from the leader sequence of other HLA molecules to CD94-NKG2 receptors. However, human cytomegalovirus can manipulate this central innate interaction through the provision of a "mimic" of the HLA-encoded peptide derived from the immunomodulatory glycoprotein UL40. Here, we analyzed UL40 sequences isolated from 32 hematopoietic stem cell transplantation recipients experiencing cytomegalovirus reactivation. The UL40 protein showed a "polymorphic hot spot" within the region that encodes the HLA leader sequence mimic. Although all sequences that were identical to those encoded within HLA-I genes permitted the interaction between HLA-E and CD94-NKG2 receptors, other UL40 polymorphisms reduced the affinity of the interaction between HLA-E and CD94-NKG2 receptors. Furthermore, functional studies using NK cell clones expressing either the inhibitory receptor CD94-NKG2A or the activating receptor CD94-NKG2C identified UL40-encoded peptides that were capable of inhibiting target cell lysis via interaction with CD94- NKG2A, yet had little capacity to activate NK cells through CD94-NKG2C. The data suggest that UL40 polymorphisms may aid evasion of NK cell immunosurveillance by modulating the affinity of the interaction with CD94-NKG2 receptors. © 2013 by The American Society for Biochemistry and Molecular Biology, Inc. Source

Bensinger W.,Fred Hutchinson Cancer Research Center | Maziarz R.T.,Oregon Health And Science University | Jagannath S.,St Vincents Comprehensive Cancer Center | Jagannath S.,Mount Sinai School of Medicine | And 8 more authors.
British Journal of Haematology

In this open-label, multicentre, phase 1 study a fully human anti-CD40 antagonist monoclonal antibody, lucatumumab, was evaluated in patients with relapsed/refractory multiple myeloma (MM). The primary objective was to determine the maximum tolerated dose (MTD) based on dose-limiting toxicities (DLTs). Secondary objectives included safety, pharmacokinetics, pharmacodynamics and antimyeloma activity. Twenty-eight patients, enrolled using a standard '3 + 3' dose escalation, received one or two (n = 3) cycles of lucatumumab 1·0, 3·0, 4·5 or 6·0 mg/kg once weekly for 4 weeks. Common lucatumumab-related adverse events were reversible, mild-to-moderate infusion reactions. Severe adverse events were anaemia, chills, hypercalcaemia and pyrexia (7% each). DLTs included grade 4 thrombocytopenia, grade 3 increased alanine aminotransferase and grade 4 increased lipase (n = 1 each). The MTD was 4·5 mg/kg. At doses ≥3·0 mg/kg, sustained receptor occupancy (≥87%), observed throughout weekly infusions up to 5 weeks after the last infusion, correlated with an estimated half-life of 4-19 d. Twelve patients (43%) had stable disease, and one patient (4%) maintained a partial response for ≥8 months. These findings indicate that single-agent lucatumumab was well tolerated up to 4·5 mg/kg with modest clinical activity in relapsed/refractory MM, warranting further study as a combination therapy. © 2012 Blackwell Publishing Ltd. Source

Deangelo D.J.,Dana-Farber Cancer Institute | Spencer A.,Malignant Haematology and Stem cell Transplantation Service | Bhalla K.N.,University of Kansas | Prince H.M.,University of Melbourne | And 10 more authors.

Panobinostat is a potent oral pandeacetylase inhibitor that leads to acetylation of intracellular proteins, inhibits cellular proliferation and induces apoptosis in leukemic cell lines. A phase Ia/II study was designed to determine the maximum-tolerated dose (MTD) of daily panobinostat, administered on two schedules: three times a week every week or every other week on a 28-day treatment cycle in patients with advanced hematologic malignancies. The criteria for hematologic dose-limiting toxicities differed between patients with indications associated with severe cytopenias at baseline (leukemia and myeloid disorders) and those less commonly associated with baseline cytopenias (lymphoma and myeloma). In patients with leukemia and myeloid disorders, 60 mg was the MTD for weekly as well as biweekly panobinostat. In patients with lymphoma and myeloma, 40 mg was the recommended dose for phase II evaluation (formal MTD not determined) of weekly panobinostat, and 60 mg was the MTD for biweekly panobinostat. Overall, panobinostat-related grade 3-4 adverse events included thrombocytopenia (41.5%), fatigue (21%) and neutropenia (21%). Single-agent activity was observed in several indications, including Hodgkin lymphoma and myelofibrosis. This phase Ia/II study provided a broad analysis of the safety profile and efficacy of single-agent panobinostat in patients with hematologic malignancies. © 2013 Macmillan Publishers Limited. All rights reserved. Source

Lee D.,Malignant Haematology and Stem cell Transplantation Service | Kalff A.,Malignant Haematology and Stem cell Transplantation Service | Low M.,Malignant Haematology and Stem cell Transplantation Service | Gangatharan S.,Peter MacCallum Cancer Center | And 6 more authors.
British Journal of Haematology

Central nervous system (CNS) multiple myeloma (MM) is exceedingly rare and portends a dismal prognosis. While immunomodulators have contributed to the improvement in survival in MM, they appear to have limited activity against CNS MM and, paradoxically, may contribute to the evolution of resistant MM clones capable of surviving within the CNS. We undertook a retrospective analysis to characterize the features of CNS MM and outcome in 17 patients from four institutions identified between 2000 and 2011. The median age was 58 years. Patients had received a median of three prior therapies and all had been exposed to at least one of the so-called novel anti-MM agents before the diagnosis of CNS MM. The median time to CNS disease from initial diagnosis was 36 months. Cerebrospinal fluid (CSF) light chain measurements produced discrepant results to serum light chain measurements in some patients. Treatments included systemic pharmacotherapy, intrathecal (IT) chemotherapy and/or radiotherapy (RT). The median overall survival (OS) from diagnosis of CNS MM was only 4 months. OS was significantly better in patients who received IT chemotherapy (20 months vs. 2 months, respectively; P < 0·02). We conclude that the systematic evaluation of IT therapy and diagnostic utility of CSF light chain measurements in CNS MM are warranted. © 2013 John Wiley & Sons Ltd. Source

Nguyen T.H.O.,Malignant Haematology and Stem cell Transplantation Service | Nguyen T.H.O.,Monash University | Sullivan L.C.,University of Melbourne | Kotsimbos T.C.,Monash University | And 3 more authors.
Immunology and Cell Biology

CD8 T cell immunity has a critical function in controlling human cytomegalovirus (HCMV) infection. In immunocompromized individuals, HCMV reactivation or disease can lead to increased morbidity and mortality, particularly in transplant recipients. In this setting, adoptive transfer of HCMV-specific CD8 T cells is a promising vaccine strategy to restore viral immunity, with most clinical approaches focussing on the use of peptides for the generation of single epitope-specific CD8 T cells. We show that using an IE1-pp65 chimeric protein as the antigen source promotes effective cross-presentation, by monocyte-derived dendritic cells (MoDCs), to generate polyclonal CD8 T cell epitopes. By exploring human leukocyte antigen (HLA)-restricted immunodominance hierarchies both within and across two immunodominant proteins, we show that HLA-B7 epitopes elicit higher CD8 T cell responses compared with HLA-A1,-A2 or-B8. This study provides important evidence highlighting both the efficacy of the IE1-pp65 chimeric protein and the importance of immunodominance in designing future therapeutic vaccines. © 2010 Australasian Society for Immunology Inc. All rights reserved. Source

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