Attenuation of vaccinia virus by the expression of human Flt3 ligand.
BACKGROUND
Vaccinia virus, one of the best known members of poxvirus family, has a wide host range both in vivo and in vitro. The expression of Flt3 ligand (FL) by recombinant vaccinia virus (rVACV) highly influenced properties of the virus in dependence on the level of expression.


RESULTS
High production of FL driven by the strong synthetic promoter decreased the growth of rVACV in macrophage cell line J774.G8 in vitro as well as its multiplication in vivo when inoculated in mice. The inhibition of replication in vivo was mirrored in low levels of antibodies against vaccinia virus (anti-VACV) which nearly approached to the negative serum level in non-infected mice. Strong FL expression changed not only the host range of the recombinant but also the basic protein contents of virions. The major proteins - H3L and D8L - which are responsible for the virus binding to the cells, and 28 K protein that serves as a virulence factor, were changed in the membrane portion of P13-E/L-FL viral particles. The core virion fraction contained multiple larger, uncleaved proteins and a higher amount of cellular proteins compared to the control virus. The overexpression of FL also resulted in its incorporation into the viral core of P13-E/L-FL IMV particles. In contrary to the equimolar ratio of glycosylated and nonglycosylated FL forms found in cells transfected with the expression plasmid, the recombinant virus incorporated mainly the smaller, nonglycosylated FL.


CONCLUSIONS
It has been shown that the overexpression of the Flt3L gene in VACV results in the attenuation of the virus in vivo.
Zurkova
Kamila
K
Institute of Hematology and Blood Transfusion, Department of Experimental Virology, U Nemocnice 1, CZ-128 20 Prague 2, Czech Republic. zurkova@uhkt.cz
Hainz
Petr
P
Krystofova
Jitka
J
Kutinova
Luda
L
Sanda
Miloslav
M
Nemeckova
Sarka
S
D000818:Animals; D002460:Cell Line; D015870:Gene Expression; D006801:Humans; D008565:Membrane Proteins / Q000235:genetics* / Q000378:metabolism; D051379:Mice; D014615:Vaccinia / Q000235:genetics / Q000378:metabolism / Q000821:virology*; D014616:Vaccinia virus / Q000235:genetics* / Q000502:physiology; D014779:Virus Replication
D008565:Membrane Proteins; C084881:flt3 ligand protein