Viruses as therapeutics Flashcards
what vectors are most commonly used in gene therapy clinical trials (virus vectors)
adenovirus
retrovirus
retrovirus vectors contain
LTRs (for integration) psi sequence (packaging) exogenous genes that replace viral genes
retrovirus vector is like a normal infec in the recipient except up until what point?
stops after integration. does not create packaged virions
advantages of retrovirus vectors
control of host range, cell and tissue tropism (change the envelope proteins to target specific cells)
disadvantages of retrovirus vectors
random integration in host chromosomes
mutagenesis upon insertion (LTR contains enhancers for transcription in T cells)
maintaining high levels of gene expression
depends on target cell prolif with MMLV-based vector
lentivirus vectors (retrovirus) enter what cells
non dividing
difference btwn adnovirus and retrovirus vectors
adenovirus vector DNA does NOT integrate into host genome
problems with the adenovirus vector
short term gene expr, as vector is not integrated into host genome
immune response
size restrictions on inserted genes
how to get around:
make gutless vectors that prevent immune response
what family is vaccinia virus in
poxvirus
what is good about vaccinia virus?
large genome so can have flexibility with size of DNA packaged
where does replication of vaccinia virus occur?
cytoplasm
where does the foregin gene get inserted to in the vaccinia genome for the vaccinia vector
non-essential site
recombination of genes for the vaccinia virus involves
recombining gene of the virus with gene from the vector
which of the viral vectors are replication incompetent?
retrovirus
adenovirus
which viral vector is replication competent
poxvirus (vaccinia0 vectors)
