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Advances in Virology
Volume 2012 (2012), Article ID 815465, 10 pages
http://dx.doi.org/10.1155/2012/815465
Research Article

Inhibition of Indoleamine-2,3-dioxygenase (IDO) in Glioblastoma Cells by Oncolytic Herpes Simplex Virus

1Department of Microbiology and Molecular Genetics, School of Medicine, University of Pittsburgh, Pittsburgh, PA 15261, USA
2Department of Human Genetics, School of Public Health, University of Pittsburgh, Pittsburgh, PA 15261, USA
3Department of Neurological Surgery, School of Medicine, University of Pittsburgh, Pittsburgh, PA 15261, USA

Received 1 March 2012; Revised 27 June 2012; Accepted 7 July 2012

Academic Editor: Julia G. Prado

Copyright © 2012 Bonnie Reinhart et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

Successful oncolytic virus treatment of malignant glioblastoma multiforme depends on widespread tumor-specific lytic virus replication and escape from mitigating innate immune responses to infection. Here we characterize a new HSV vector, JD0G, that is deleted for ICP0 and the joint sequences separating the unique long and short elements of the viral genome. We observed that JD0G replication was enhanced in certain glioblastoma cell lines compared to HEL cells, suggesting that a vector backbone deleted for ICP0 may be useful for treatment of glioblastoma. The innate immune response to virus infection can potentially impede oncolytic vector replication in human tumors. Indoleamine-2,3-dioxygenase (IDO) is expressed in response to interferon γ (IFNγ) and has been linked to both antiviral functions and to the immune escape of tumor cells. We observed that IFNγ treatment of human glioblastoma cells induced the expression of IDO and that this expression was quelled by infection with both wild-type and JD0G viruses. The role of IDO in inhibiting virus replication and the connection of this protein to the escape of tumor cells from immune surveillance suggest that IDO downregulation by HSV infection may enhance the oncolytic activity of vectors such as JD0G.