In vivo complementation studies of a glycoprotein H-deleted herpes simplex virus-based vector.
The utilization of herpes simplex virus (HSV) as a vector for gene delivery to the nervous system or as a live vaccine delivery system is dependent on the construction and characterization of disabled virus mutants which are unable to cause disease. Under certain circumstances, however, replication-defective vectors may carry a potential risk if they can be efficiently complemented by a co-infecting wild-type virus. Stocks of defective vectors should, therefore, be free from replication-competent virus, and helper cell lines should be incapable of generating replication-competent virus by recombination between the vector and the complementary gene. We describe a glycoprotein H-negative (gH-) virus/helper cell line combination which generates helper-free defective virus stocks containing replication-competent virus at a frequency no higher than 1 in 10(9) p.f.u. This virus/helper cell system provides a suitable background for the construction of safe replication-defective gene delivery vectors. In vivo studies demonstrate that gH- virus is unable to initiate disease in mice and establishes latency at low efficiency compared to wild-type HSV. To determine whether gH- virus can be complemented by wild-type virus in vivo, mice were infected with a variety of mixtures of these viruses. Complementation was observed in a minority of animals infected with more than 10(6) p.f.u. of both wild-type and defective virus but the most common observation was that the presence of defective virus suppressed entry of wild-type virus into the nervous system.
Department of Pathology, University of Cambridge, UK.
P G
PG
Speck
S
S
Efstathiou
A C
AC
Minson
D000818:Animals; D002460:Cell Line; D002522:Chlorocebus aethiops; D006224:Cricetinae; D003673:Defective Viruses / Q000235:genetics* / Q000502:physiology; D005260:Female; D005727:Ganglia, Spinal / Q000473:pathology / Q000821:virology; D017353:Gene Deletion; D005816:Genetic Complementation Test; D005822:Genetic Vectors; D006561:Herpes Simplex / Q000473:pathology / Q000821:virology; D018259:Herpesvirus 1, Human / Q000235:genetics* / Q000502:physiology; D006801:Humans; D051379:Mice; D008807:Mice, Inbred BALB C; D014709:Vero Cells; D014759:Viral Envelope Proteins / Q000235:genetics*; D017735:Virus Latency; D014779:Virus Replication
D014759:Viral Envelope Proteins; C044200:glycoprotein H, herpes simplex virus type 1