PEG precipitation, what kinds of PEG I should use? - virology (Mar/22/2005 )

I am trying to concentrate Dengue virus to get a high titer for long RT-PCR amplification. I read some protocols, seems the PEG is the relatively simple one, but different authors use different PEGs ( 10000, 8000, 6000), does anyone have some suggestions on PEG precipitation of Dengue virus?
Thanks:-).

Hi Franklincon,

do you know this paper:

M. Flamand, F. Megret, M. Mathieu, J. Lepault, F.A. Rey, and V. Deubel (1999) Dengue Virus Type 1 Nonstructural Glycoprotein NS1 Is Secreted from Mammalian Cells as a Soluble Hexamer in a Glycosylation-Dependent Fashion. Journal of Virology 73 (7): 6104-6110

They used PEG 6000.

Best regards,
Marion

Thank you very much, Marion,
I will try it this time. I ever tried 10000, but seems cannot work well. I don't know it is because the 1000 I used or the cells I chose cann't support dengue growth very well. I will try again and use 6000.
Thank you very much for your reply.
Best wishes,
Frank