Phage MOI value and its significance

MOI is an abbreviation for multiplicity of infection, Chinese translated as infection complex. The traditional MOI concept originated from the
of phages
infected bacteria.
means the ratio of phages to bacteria at the time of infection, i.e. the average number of phages infected per bacterium. The number of phages is pfu. MoI is generally considered to be a ratio, with no units, but its implied unit is pfu number/cell. MOI was later widely used in the study of virally infected cells, meaning the ratio of viruses to the number of cells at the time of infection.
, moI has different meanings because the number of virus units is represented differently.
the number of viruses, such as adenovirus and herpes simplex viruses, which can produce cleavage effects, still traditionally use pfu to indicate the number of viruses, so their MOI means the same as traditional concepts. For some viruses, such as AAV viruses, pfu cannot represent the number of viruses, but instead uses TU, IU, virus particles (viral particles, v.p) or
gene
groups (vector genome, v.g.) to indicate the number of viruses, so its MOI has a different meaning. With TU or IU, MOI means TU/cell or IU number/cell. With v.p., MOI means v.p. number/cell 。 With v.g, MOI means v.g. number/cell。
can be divided into two different MOI modality:
1) in active units, such as pfu, TU, IU. The meaning of MOI at this time refers to the average number of active units per cell infected with the virus.
2) represents the number of viruses,
v.p.
v.p. or v.g., in terms of virus particles or the number of genomes. MoI then refers to the average number of virus particles or genomes infected with the virus per cell. It is worth mentioning that the above two different MOI means are different in meaning and value. The former is the traditional sense of MOI, the former MOI means more simplified and intuitive, but also gradually adopted by some researchers. The principle of MOI in the traditional sense is based on the fact that infected cells are random events, following the poisson distribution pattern, and calculating the complex number of infections (MOI) required to infect a certain percentage of
cultured
cells.
the formula is: P (k) - 1- P (0), P (0) - e-m or m - InP (0). Where: P (k) is the percentage of infected cells, p(0) is the percentage of uninsected cells, m is MOI value. For example, if you want to infect 99% of the cultured cells in a petri dish, then: P(0) - 1% - 0.01 m - -In (0.01) - 4.6 pfu/cell.
can be seen that due to the virus characteristics and researchers' habits, moI units from the original convention of pfu number/cell into a variety of units of the express. When reading literature and writing papers, you should pay attention to the specific meaning and unit of MOI.