# Maximum possible virus titers

James Andreasen andreasj at ccmail.orst.edu
Tue Aug 22 08:49:40 EST 1995

In article <DDF67C.BwJ at ncifcrf.gov> tobin at fcs260c.ncifcrf.gov (Greg Tobin) writes:
>>> Is there a theoratical maximum for the number of virus progeny a cell
>>> culture supernatant can have?
>>> Is there any possibility of a titer of 10^-23(TCID50/ml) in any of the virus
>>> infected cell culture supernatant ?
>>> I would appreciate if someone could answer these questions.
>>
>I recall poliovirus stocks with titers around 10^10 per ml or 10^12 particles
>per ml.  10^23 seems much too high.  Look at the size of a lentivirus:

>120 nM (120 x 10^9 M) in diameter
>8 x 10^6 particles along a one meter line
>5 x 10^14 particles packed into a cubic centimeter (one ml)
>5 x 10^20 particles packed into a cubic meter

>Greg Tobin, Ph.D.                        tobin at lcms-1.ncifcrf.gov

Tobin's calculation of 5 x 10^14 particles in one cc is an approximation of
the theoretical maximum titer of any virus and would exceed the
theoretical maximum titer for a large virus.   10^23 is approximately
Avogadro's number, is it not?  Think about the implications of that number of
any particles, whether they be atoms, molecules, or virions, as far as the
mass of that quantity and the volume the mass would have to occupy!

James Andreasen  DVM, PhD      andreasj at ccmail.orst.edu