Abstract
One intracerebral passage of either the parent egg seed (PES) or an attenuated variant (10t) of the Trinidad strain of Venezuelan equine encephalomyelitis (VEE) virus in young adult mice produced progeny that were no longer differentiated unequivocally on the basis of plaque size. Plaques averaging about 2 mm in diameter, which was somewhat smaller than those formed by the PES virus and larger than those of the 10t strain, were formed by both strains. Seven serial passages of the PES virus in mouse brain failed to alter its virulence appreciably. In contrast, passage in mouse brain progressively changed the properties of the attenuated 10t strain. A substrain was isolated that possessed virulence similar to that of the PES virus and formed small plaques similar to those of the 10t strain. These findings showed a unique dissociation between the plaque size and virulence of the 10t strain. The new substrain differed from the PES virus and the 10t strain in its capacity for growth in mouse tissues after intraperitoneal inoculation. The substrain multiplied poorly in splenic tissue, which supports growth of the PES and 10t strains, but grew to high titers in the brain, which does not support appreciable growth of the 10t strain.
Full text
PDF
Selected References
These references are in PubMed. This may not be the complete list of references from this article.
- HEARN H. J., Jr A variant of Venezuelan equine encephalomyelitis virus attenuated for mice and monkeys. J Immunol. 1960 Jun;84:626–629. [PubMed] [Google Scholar]
- HEARN H. J., Jr Differences among virus populations recovered from mice vaccinated with an attenuated strain of Venezuelan equine encephalomyelitis virus. J Immunol. 1961 Nov;87:573–577. [PubMed] [Google Scholar]
- HEARN H. J., Jr, RAINEY C. T. CROSS-PROTECTION IN ANIMALS INFECTED WITH GROUP A ARBOVIRUSES. J Immunol. 1963 May;90:720–724. [PubMed] [Google Scholar]
- Hearn H. J., Jr, Soper W. T. Properties of Venezuelan equine encephalomyelitis virus accompanying attenuation in vitro. J Virol. 1967 Jun;1(3):453–459. doi: 10.1128/jvi.1.3.453-459.1967. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Heydrick F. P., Wachter R. F., Hearn H. J., Jr Host influence on the characteristics of Venezuelan equine encephalomyelitis virus. J Bacteriol. 1966 Jun;91(6):2343–2348. doi: 10.1128/jb.91.6.2343-2348.1966. [DOI] [PMC free article] [PubMed] [Google Scholar]
- MUSSGAY M. GROWTH CYCLE OF ARBOVIRUSES IN VERTEBRATE AND ARTHROPOD CELLS. Prog Med Virol. 1964;6:193–267. [PubMed] [Google Scholar]