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Title: SINDBIS VECTORS SUPPRESS SECRETION OF SUBVIRAL PARTICLES OF JAPANESES ENCEPHALITIS VIRUS FROM MANMALIAN CELLS INFECTED WITH SIN-JEV RECOMBINANTS

Author
item PUGACHEV, KONSTANTIN - UNIVERSITY OF GEORGIA
item Mason, Peter
item FREY, TERYL - UNIVERSITY OF GEORGIA

Submitted to: Virology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/1/1995
Publication Date: N/A
Citation: N/A

Interpretive Summary: Japanese encephalities (JE) is a disease that infects pigs, horses, and humans in many areas of the far east and Southeast Asis, that is caused by a mosquito-borne virus called Japanese encephalitis virus (JEV). JEV infection of pregnant swine results in the birth of litters of pigs with a high percentage of stillbirths or pigs affected with encephalitis, an infection of the brain. The virus can also cause a lethal encephalitis in man and horses. We have been involved in the development of recombinant DNA-derived vaccines to prevent JE in man and domestic animals. Our earlier studies targeted the production of genetically engineered vaccinia virus vaccines to deliver JEV proteins to inoculated animals. Although these products show promise, previous exposure to vaccinia virus can interfere with their effectiveness. To overcome this problem, we have explored alternative delivery systems to produce genetically engineered JE vaccines. This manuscript describes the properties of one of these alternative JE vaccines based on genetically engineered Sindbis virus, and demonstrates that the configuration of the genetically engineered vaccine itself may interfere with its ability to protect the vaccinate from disease. Although these findings may not eliminate the usefulness of Sindbis virus-based JE vaccines, understanding of this interference phenomenon could help the production of better vaccines.

Technical Abstract: Double-subgenomic Sindbis virus (dsSIN) recombinants that express cassettes encoding prM-E or a C-terminally truncated form of E of Japanese encephalitis virus (JEV) were constructed. The products were efficiently expressed in both mammalian and mosquito cell lines infected with the dsSIN recombinants. However, suppression of prM-E secretion from mammalian cells infected with dsSIN-prM-E recombinants was observed. This suppression was more pronounced late in infection(<5% of total product was secreted during an 8-hr chase) than early in infection (15% secretion during a 6-hr chase). In contrast, secretion of prM-E from dsSIN-prM-E-infected mosquito (C6/36) cells was found to be efficient (>50% during an 8-hr chase). The prM-E secreted from both mammalian and mosquito cells was in the form of subviral particles as determined by velocity gradient centrifugation, sensitivity to nonionic detergent, and analysis of processing of N-linked glycans. Coinfection experiments with vaccinia virus vP829 (E. Konishi et al. (1991) Virology 18 401-410) + SIN demonstrated that the reduced level of secretion of subviral particles exhibited by the dsSIN-JEV recombinants was due to an inhibitory effect of the dsSIN vectors. The suppression of subviral particle secretion as apparently correlated with the inhibition of cell protein synthesis which is mediated in SIN-infected vertebrate cells by expression of the SIN nonstructural proteins.