freezing retrovirus supernatant

[Ashok Aiyar]

On 10 Sep 2001 13:42:19 +0100,
    "Wolfgang Schechinger" (wolfsc at ibms.sinica.edu.tw) wrote:
> Hi all, 
> 
> a quick question, a quick answer is desired. I have some supernatant of 
> retrovirus producing cells). Is it possible to simply freeze the supernatant or 
> should I concentrate the virus (how? - this is another question) and add 50% 
> glyzerol.

Depends on the envelope.  Pantropic virions pseudotyped with VSV-G 
appear to withstand 1 - 2 rounds of freeze-thaw with no significant 
loss of infectivity (as measured by GFP expression after infection).

Viruses with the amphotropic envelope are more susceptible to 
freeze-thaw.

We don't add any glycerol.  Just flash freeze in a dry-ice/ethanol
bath or liquid nitrogen.  Quick thaw at 37oC.  Stocks frozen 
slowly (1oC/min) at -80oC lose infectivity more rapidly.

Ashok

-- 
Ashok Aiyar                                   a-aiyar at northwestern.edu  
Department of Microbiology-Immunology           office: (312) 503-2524
303 E. Chicago Avenue, WARD 4-123                  lab: (312) 503-2542
Northwestern University, Chicago, IL 60611         fax: (312) 503-1339