Development of Methods for Safe Application of Viral Vectors for Production of Gene-Engineering Vaccines

Abstract

Vaccine avipoxviral strains FK (fowl) and Dessau (pigeon) were adapted for replication in heterologous for them mammalian cells from the embryonic bovine trachea cell line EBTr. A proof for their successful adaptation was the cytopathic effect (CPE) on mammalian cell cultures, expressed in appearance of cells with round shape, cytoplasmic vacuolization and detachment of the cells from the substrate. In application of low initial infections titers of 10 3 CCID50/ml (high initial dilutions of 10-3 CCID50/ml, respectively) of the viral suspension for both eventually attenuated by many passages from the heterologous for mammals and mammalian cells avian vaccine strains, but no CPE was established. In freezing of the so inoculated with the diluted viral suspensions mammalian cells after addition of cryoprotector Dimethylsulfoxide (DMSO), thawing and re-incubation in fresh cultivation medium, signs of activated cell proliferation (as decreased monolayer density and formation of internal "islands" of cells in the monolayer) were noted. One of the possible explanations could be eventual transfer of nucleotide sequences from viral particles to separate cells because of activated fusion processes on the influence of DMSO in drastic temperature changes. The results obtained proposed a possibility about application of the described methods as available alternatives for production of geneengineering vaccines, and were in confirmation with scientific references. Furthermore, a possibility for production of membrane glycoprotein receptors and other immune molecules from non-immune cells in appropriate conditions (presence of viral particles) was suggested, which was also in agreement with literature findings. Future studies are necessary in this direction, directed mainly to isolation and purification of the eventually received recombinant viral