The current USDA licensed vaccine, live E. ictaluri AQUAVAC-ESC® (Intervet Inc ., has been selected by multiple passages in increased concentrations of the antibiotic rifampicin [21], [22], [23].
However, the correlation between VHEV and Vilyuisk encephalomyelitis is still uncertain because VHEV has been isolated by multiple passages in mice and thus may represent a highly divergent strain of TMEV.
The A/Aquatic bird/Korea/W81/2005 (H5N2), isolated from a wild bird in Korea in 2006, kindly provided by Dr. Young-Ki Choi, Chungbuk University, Korea, was adapted by multiple passages (15 times) in BALB/c mice.
The NSCs co-cultured with Cd-MECs retained self-renewal capacity, as evidenced by multiple passages (> 3) of structures formed in Matrigel.
Traditionally attenuation was achieved simply by multiple passages of the microorganism on growth medium, in animals, eggs or cell cultures or by chemical or physical mutagenesis, which resulted in random mutations that lead to attenuation.
The ability to predictably attenuate B. bovis by multiple passages through splenectomized cattle has been used in Babesia endemic regions to produce the only available vaccine that can protect animals from severe clinical disease [ 11, 25].
FP9 is a fully sequenced, live, highly attenuated form of a European strain of Fowlpox virus, derived by multiple passages of the wild-type Fowlpox virus in avian cells.
Therefore, Enterobacter agglomerans was isolated from mosquitoes and selected for midgut survival by multiple passages through mosquitoes.
The fact that genomic alterations are conserved for several years, without any major changes, as demonstrated by sequential CGH analysis after multiple passages in vivo, suggests that genomic profiles remain relatively stable over time despite new selection pressures and loss of human stroma.
We also evaluated the genetic stability of the CVB4/p24 733) recombinant after multiple passages in cell culture, at low multiplicities.
