Avian reovirus

More recently, triple /1-spiral repeats have been identified in mammalian reovirus type 3 fiber (Chappell et al., 2002 Fig. 4A), avian reovirus fiber (Guardado Calvo et al., 2005 Fig. 4B), and bacteriophage PRD1 P5 protein (Merckel et al., 2005 Fig. 4C). In the latter two cases, it appears that only two repeats are present, just N-terminal to the head domain. Mammalian reovirus fiber contains eight putative triple /1-spiral repeats, of which three were resolved in the crystal structure (Chappell et al., 2002). 

Guardado Calvo, P., Fox, G. C., Hermo Parrado, X. L., Llamas-Saiz, A. L., Costas, C., Martinez-Costas, J., Benavente, J., and van Raaij, M. J. (2005). Structure of the carboxy-terminal receptor-binding domain of avian reovirus fibre sigmaC. / Mol. Biol. 354, 137-149. 

Benavente, J. Shatkin, A.J. Avian reovirus mRNAs are nonfunctional in infected mouse cells translational basis for virus host-range restriction. Proc. Natl. Acad. Sci. USA, 85, 4257-4261 (1988)... 

Duncan, R. The low pH dependent entry of avian reovirus is accompanied by two specific cleavages of the major outer capsid protein m2C. Virology 1996, 219. 179- 189. 

Host mediated virus restriction has been studied in bacteriophage (1), in oncornaviruses (murine leukemia viruses) (2), adenoviruses (3), avian reovirus (4) and Sendai (5) The mechanisms involved appear to be quite different for each system. None of these studies involves inhibition of virus replication by interferon, a topic discussed elsewhere in this volume. 

The oncolytic viruses include adenovirus, measles, reovirus, vesicular stomatitis virus (VSV),HSV,poxvirus, and vaccinia. Specific examples include (1) ONYX-015, which is an adenoviral oncolytic virus, administered to patients with liver metastases of colorectal cancer and pancreatic cancer [29], (2) Reolysin, which is an oncolytic reovirus administered to patients with glioma [30], and (3) MV-CEA, which is an oncolytic measles virus expressing carcinoembryonic antigen, administered to patients with ovarian cancer [31]. Some oncolytic viruses are wild type and are apparently not pathogenic in humans, such as the Newcastle disease virus (NDV), which is an RNA avian paramyxovirus. PV701, a naturally attenuated, replication-competent strain of NDV, has been administered to patients with advanced solid tumors [32], The applicability of oncolytic viruses as a therapy for clinical oncology trials is due to their potential selectivity the ability to kill tumor cells but not normal cells. However, the level of attenuation of viral replication in normal cells is limited for most oncolytic vectors. 

---