Tick-borne encephalitis flavivirus

Despite the protective effect of NO against various viral infections, workers in several studies have shown a harmful role of NO in many systems. NO seems to play a part in the development of pneumonia caused by influenza virus [128], in the pathogenesis in mice of tick-borne encephalitis flavivirus infection [131], and in worsening the course of the murine myocarditis caused by coxsackievirus B3 [132]. In addition, pneumonia in mice induced by herpes simplex virus type 1 could be suppressed by the inhibitor of iNOS [133]. The issue of whether NO acts as an inhibitor of viral replication or as a harmful agent, therefore, remains unanswered. This issue is particularly evident in HIV-1 infection, since NO seems to act as a double-edged sword in the pathogenesis of HIV-1. 

Flaviviruses are included among the enveloped viruses recently reported as dependent on cell surface HS to efficiently initiate cell infection. An involvement of HS during attachment and entry through its binding to the virion envelope glycoprotein E was initially demonstrated for DENV [82] and then extended to YFV [83], tick-borne encephalitis virus (TBEV) [84], and Murray Valley encephalitis virus (MVEV) [85], as well as to hepatitis C virus (HCV), a member of the Hepacivirus genus of Flaviviridae [86]. 

Although there are mechanistic differences between retroviruses, paramyxoviruses, and the orthomyxovirus influenza, the viruses discussed to this point have definite structural and functional similarities including spikelike, trimeric native structures and the presence of coiled coils in their fusion-active subunits. The flaviviruses and alphaviruses, however, appear to be another class of enveloped viruses entirely. Flaviviruses include yellow fever. West Nile virus. Dengue virus, and tick-borne encephalitis virus (TBEV). Alphaviruses, of the togavirus family, include... 

Schalich, J., Allison, S. L., Stiasny, K., Mandl, C. W., Kunz, C., and Heinz, F. X. (1996). Recombinant subviral particles from tick-borne encephalitis virus are fusogenic and provide a model system for studying flavivirus envelope glycoprotein functions. 

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