For figuring out the amount of irus you need to add for a certain MOI,
use the formula: #cells * desired MOI= total PFU (or Plaque Forming
Units) needed. Then use the formula: (total PFU needed) / (PFU/ml) =
total ml of irus needed to reach your desired dose.
坚持看完举例：
For example: You hae a irus with a titer of 1.3x1011 PFU/ml and a well
that contains 1.8x106 cells. You want to make that well contain 200 MOI.
Therefore, formula 1: (1.8x106 cells ) * (200 MOI) = 3.6x108 PFU
desired. Then, formula 2: (3.6x108 PFU desired) / (1.3x1011 PFU/ml) =
0.0028 ml or 2.8μl. Add the 2.8μl to the well and label it 200 MOI.