How can harvest time affect the GoStix Value?

The GoStix Value (GV) is proportional to the amount of p24 protein produced, which in turn correlates with the length of the time to harvest. Therefore, a longer harvest time will result in a larger GV (ng/ml p24), assuming that other conditions (e.g., packaging system, transfection method, etc.) are kept constant. The data demonstrated that the ratio between GV and IFU/ml varies depending on the harvest time, which is why harvest time must be kept constant to enable calculation of IFU/ml from GV, and for comparison across experiments.