Hi! I'm not sure about TCD, but TCID stands for tissue culture infectious
dose, that is, how much virus do it take to infect the tissue cluture, and
it is normally TCID50 which is how much virus does it take to infect 50% of
the culture; using 50% because this gives us the most accurate results.
!00% infection of the culture can give us scewed data. You may com across
EID, egg infectious dose (eg. Influenze is infected into eggs and studied),
LDI, Lethal dosage, which is the same as TCID but instead of just infection
the lethality of your test organism is studied. All of these tests are done
with studying how much virus is required to have an effect, what ever it is
you are studying, on 50% of your test organism ie. host.
Hope this helps!
Ruth B Hamilton <ruthh at zoo.cam.ac.uk> wrote in message
news:Pine.GSO.3.95.990923162959.27976J-100000 at parasite...
> I have been reading some fairly old virology papers which have measured
viral
> titres in log(10)TCD (I have also seen TCID). So far my searches of
textbooks,
> journals and websites haven't been able to define what this means. Any
> explanation would be very helpful.
> Ruth
>>>>
