Evaluation of Factors Related to Growth of Rift Valley Fever Virus in Suspended Cell Cultures

Walker, Jerry S.; Carter, Richard; Klein, Frederick; Snowden, Shirley E.; Lincoln, Ralph E.

doi:10.21236/ad0850080

Cited by 2 publications

(3 citation statements)

References 1 publication

Supporting

Mentioning

Contrasting

Order By: Relevance

“…6). This result has previously been observed for RVFV in both monolayer and suspended cell cultures, for which it was shown that the MOI had no effect on the titer of virus reached; it had an effect merely on the time taken to reach the peak titer in a given cell line (49). When the titers of r2segMP12-infected cell supernatants were examined, there was a 1,000-fold decrease in titer between cells infected at 0.005 PFU/cell and 5 PFU/cell.…”

Section: Discussionsupporting

confidence: 82%

Creation of a Recombinant Rift Valley Fever Virus with a Two-Segmented Genome

Brennan

Welch

McLees

et al. 2011

J Virol

View full text Add to dashboard Cite

Rift Valley fever virus (RVFV; family Bunyaviridae) is a clinically important, mosquito-borne pathogen of both livestock and humans, which is found mainly in sub-Saharan Africa and the Arabian Peninsula. RVFV has a trisegmented single-stranded RNA (ssRNA) genome. The L and M segments are negative sense and encode the L protein (viral polymerase) on the L segment and the virion glycoproteins Gn and Gc as well as two other proteins, NSm and 78K, on the M segment. The S segment uses an ambisense coding strategy to express the nucleocapsid protein, N, and the nonstructural protein, NSs. Both the NSs and NSm proteins are dispensable for virus growth in tissue culture. Using reverse genetics, we generated a recombinant virus, designated r2segMP12, containing a two-segmented genome in which the NSs coding sequence was replaced with that for the Gn and Gc precursor. Thus, r2segMP12 lacks an M segment, and although it was attenuated in comparison to the three-segmented parental virus in both mammalian and insect cell cultures, it was genetically stable over multiple passages. We further show that the virus can stably maintain an M-like RNA segment encoding the enhanced green fluorescent protein gene. The implications of these findings for RVFV genome packaging and the potential to develop multivalent live-attenuated vaccines are discussed. Rift Valley fever virus (RVFV)is an emerging pathogen capable of causing serious epidemics among livestock and humans. Originally isolated in sub-Saharan Africa, the virus has spread northward to Egypt and the Arabian peninsula (43) and has resulted in huge economic losses of domesticated animals as well as more than a thousand human deaths. In ruminants, particularly sheep and cattle, RVFV disease is characterized by fetal deformities, abortion, and high rates of mortality among young animals (44). In humans, the disease can progress from self-limiting febrile illness to hemorrhagic fever, encephalitis, or retinal vasculitis. RVFV is predominantly transmitted by mosquitoes, and the virus has been isolated from more than 40 species in nature, while under laboratory conditions many different arthropods are capable of transmitting the virus (reference 46 and references therein). In an era of climate change, the spread of competent insect vectors into "virgin" territories is a major public health concern, making RVF a potential worldwide human, animal, and economic threat (12).RVFV is a member of the Phlebovirus genus in the Bunyaviridae family and contains a tripartite single-stranded RNA (ssRNA) genome comprising two negative-sense and one ambisense segment (reviewed in reference 7). The large (L) segment (approximately 6.4 kb) codes for the viral RNA-dependent RNA polymerase (L protein). The medium (M) segment (approximately 3.8 kb) encodes four proteins in a single open reading frame (ORF): the precursor to the virion envelope glycoproteins Gn and Gc and two other proteins called NSm (or NSm2) and 78K (or NSm1), depending on which of five methionine codons that translation initiates f...

show abstract