Biological Safety Manual - University of Florida

Non-integrating-so cannot obtain stable, long-term expressionBroad tropism so can infect non-target tissueCan cause common cold if replication competent virus is generated. This hazard is minimized byusing replication defective vectors.References: James N. Warnock, Claire Daigre, & Mohamed Al-Rubeai. Introduction to viral vectors. Methodsin Molecular Biology (2011) 737: 1-25. Shenk, T.E. Adenoviridae: the viruses and their replication. In Fields Virology, Fields, B.N., &Knipe, D. (Eds.). Philadelphia: Lippincott, Williams, and Wilkins, 2001; 2265-2300. Raper, S.E., Chirmule, N., Lee, F.S., Wivel, N.A., Bagg, A., Gao, G.P., et al. Fatal systemicinflammatory response syndrome in an ornithine transcarbamylase deficient patient followingadenoviral gene transfer. Mol Genet Metab 80: 148-158 (2003) Hutchins, B., Sajjadi, N., Seaver S., Shephard, A., Bauer, S.R., Simek, S., et al. Working towardan adenoviral vector testing standard. Mol Ther 2:532-534 (2000)Baculovirus:Baculoviruses are a group of enveloped, double-stranded DNA viruses capable of infecting certaininvertebrate species but incapable of infecting or replicating in mammals or plants. Autographicacalifornica multiple nucleopolyhedrovirus (AcMNPV) is most commonly used. The vector is generatedusing established insect cell lines. Experimental work with Baculovirus vectors is generally recommendedat BSL-1. Based on the risk assessment, biosafety levels maybe higher if the vector is cloned withoncogenic/toxic inserts.Advantages of using Baculovirus Vectors: Non-infectious to human cell lines Do not replicate in mammalian cells Do not induce antibody production in humans Can accommodate very large inserts (up to 38Kb) Promising human gene therapy toolDisadvantages of using Baculovirus Vectors: Rapidly inactivated by complementReference: James N. Warnock, Claire Daigre, & Mohamed Al-Rubeai. Introduction to viral vectors. Methodsin Molecular Biology (2011) 737: 1-25.Herpes simplex virus (HSV):HSV is a linear double stranded, enveloped DNA virus belonging to Family Herpesviridae. The large andcomplex genome is covered by a capsid which, in turn is surrounded by an envelope. HSV-1 is mostcommonly used as a vector.Viral Replication: Initially, the viral envelope attaches to host cell receptors. Fusion of the receptor withthe envelope creates pores through which the virus enters the host cell. Early, then late proteins aretranscribed. The genome enters the nucleus where the virus is packaged. HSV-1 can either go to a lyticphase in which the cell is lysed to release the virus or a latent phase in which it can remain dormant in ahost cell for a long time.Three types of HSV-1 based vectors have been developed: Recombinant replication competent vectors which have deleted accessory genes. These aregenerally used as oncolytic viruses.23