A flow cytometry-based assay for quantifying non-plaque forming strains of yellow fever virus.

Autor: Erika Hammarlund, Ian J Amanna, Melissa E Dubois, Alex Barron, Flora Engelmann, Ilhem Messaoudi, Mark K Slifka
Jazyk: angličtina
Rok vydání: 2012
Předmět:
Zdroj: PLoS ONE, Vol 7, Iss 9, p e41707 (2012)
Druh dokumentu: article
ISSN: 1932-6203
DOI: 10.1371/journal.pone.0041707
Popis: Primary clinical isolates of yellow fever virus can be difficult to quantitate by standard in vitro methods because they may not form discernable plaques or induce a measurable cytopathic effect (CPE) on cell monolayers. In our hands, the Dakar strain of yellow fever virus (YFV-Dakar) could not be measured by plaque assay (PA), focus-forming assay (FFA), or by measurement of CPE. For these reasons, we developed a YFV-specific monoclonal antibody (3A8.B6) and used it to optimize a highly sensitive flow cytometry-based tissue culture limiting dilution assay (TC-LDA) to measure levels of infectious virus. The TC-LDA was performed by incubating serial dilutions of virus in replicate wells of C6/36 cells and stained intracellularly for virus with MAb 3A8.B6. Using this approach, we could reproducibly quantitate YFV-Dakar in tissue culture supernatants as well as from the serum of viremic rhesus macaques experimentally infected with YFV-Dakar. Moreover, the TC-LDA approach was >10-fold more sensitive than standard plaque assay for quantitating typical plaque-forming strains of YFV including YFV-17D and YFV-FNV (French neurotropic vaccine). Together, these results indicate that the TC-LDA technique is effective for quantitating both plaque-forming and non-plaque-forming strains of yellow fever virus, and this methodology may be readily adapted for the study and quantitation of other non-plaque-forming viruses.
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