Analysis of baculovirus aggregates using flow cytometry.
J Virol Methods
; 134(1-2): 8-14, 2006 Jun.
Article
em En
| MEDLINE
| ID: mdl-16364459
ABSTRACT
Aggregation of viral particles represents a significant problem for baculoviral stock processing and storage. Aggregation may also affect the results of viral particle counting. A method using flow cytometry was previously developed in our lab to measure the concentration of baculovirus particles produced in insect cell cultures. In the present study, the use of the flow cytometry method was extended to the detection of baculovirus aggregates. Flow cytometry analysis of freshly prepared baculovirus stocks, stained with SYBR Green, generally exhibited a single unimodal distribution; while, baculovirus stocks stored at 4 degrees C for a few months exhibited a bimodal distribution of the fluorescent intensity signal. The bimodal distribution was associated with a decrease in the size of the original viral population and an emergence of a new viral population with a high fluorescence intensity. Treatment of these samples with an endonuclease (Benzonase) confirmed that the new population observed in the flow cytometry analysis is not free cellular DNA. Filtration through 0.22 and 0.45 microm membranes of the stored samples prior to flow cytometry analysis confirmed that the high fluorescence intensity population involved particles larger than a single baculovirus. Exposing freshly amplified baculovirus stocks with a unimodal distribution to a pH of 5.3, a condition known to induce aggregation, showed the emergence of a second population with a bimodal distribution. These results suggest that flow cytometry analysis could be used to detect baculovirus aggregates. The aggregates were associated with high fluorescence intensity populations and the mean green fluorescence intensity of these populations could be used as an indicator of the mean aggregate size.
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Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Baculoviridae
/
Citometria de Fluxo
Tipo de estudo:
Diagnostic_studies
Limite:
Animals
Idioma:
En
Revista:
J Virol Methods
Ano de publicação:
2006
Tipo de documento:
Article