What is titration of viral progeny?
Posted 11 July 2012 - 12:28 AM
Posted 11 July 2012 - 12:32 AM
Posted 11 July 2012 - 01:18 AM
Plaque assay is really difficult to do in our case. Although my virus leaves plaques in some certain cell type, it kills most other cell lines. therefore, the only titration I can do is HA test.
Posted 11 July 2012 - 01:41 AM
Posted 11 July 2012 - 05:07 AM
I presume that you have mentioned this in your manuscript and the reviewer has a problem with it because it isn't a measure of infectious virus?
You can do as bob1 says, and do a TCID50 assay.
As for plaque assay, why not just use the cell line that your virus does cause plaques in then?
Which virus are you working with? What do other labs that use this virus typically use to quantify stocks?
Posted 11 July 2012 - 08:41 AM
Also, im not sure if it is technically correct to use the plaque assay titer that i obtained from Vero cells on human cancer cells, which in my case is HCT116. do you understand what im saying? some might argue that it's alright, but the nature and size of cells are different and i dont like that.
Bob1, thanks as usual mate, that is actually what im gonna do. im going to add some tcid50 data.
Sorry for lowercase words, im typing from mobile.
Posted 11 July 2012 - 06:36 PM
I disagree that this is an issue. You have to think about what the plaque assay is for. I think you are over thinking it.
What you are measuring is the infectivity of that stock, in Vero in your case.
This then gives you a measure for the infectivity of your stock- so that your input dose for your experiments is the same. It doesn't matter if your virus infects the human lines differently to Vero, because the dose of virus that you put in will be the same- as determined by plaque assay.
I don't think I'm explaining this very well
Anyway, the point is that using a measure of infectivity (such as TCID50 or plaque assay) will be preferable to HA assays where non-infectious and defective particles can skew your results.
Posted 11 July 2012 - 08:12 PM
Now, we usually infect cells 30 HA for 10^5 cells. This is standard protocol. Maybe I can use pfu to satisfy him?
Posted 11 July 2012 - 09:19 PM
I don't think it is reasonable to simply say 1HA = 3x10^5 pfu , so therefore 30 HA = 9x10^6 pfu, the relationship might not be linear.
You could however, in my opinion, take your 30HA dose and perform a plaque assay on it. Then say that your 30 HA dose has a plaque assay titre of x.