In a paper recently I saw "Cell are infected with 50,000 IU of virus per 100ul well". I can not seem to find a defintion of this unit? Is it a functional unit or just a count? If someone is familiar with this definition please let me know.
It is a retrovirus. The thesis is here (page 18): https://tspace.library.utoronto.ca/bitstream/1807/98170/3/Mazzanti_Andrew_D_201911_MSc_thesis.pdf